In order to speed things up, let us take a brief look at the other principal characters and their main traits, and how translators handle them:
Frederick is an amiable fellow and also the young sister-son of Ebeneezer Scrooge himself, thus his language ought at least to convey nuances of this cheerfulness youth that contrasts itself to the rigid miserliness of his uncle - since the two are very much opposites at the beginning of the story.
Both Shibaji, Benibara (whose translation stems from 1911) and Hataya give Fred's first person pronouns as watashi, and watakushi (when he is especially formal). Using the plurals affixed with -tachi and -domo, the latter being the most humble and formal. Yaguchi, Morita, Yamanaka and Yamamoto use boku and boku-tachi as he is singular and plural pronouns, the informal boyish first person pronoun - when he is being in a less tense situation - Shibaji, Benibara and Hataya have him use watashi regardless of this. Nakajima and Hori (1928) give it as ore and ore-tachi, the assertive male pronoun giving him a much more mature vibe, versus that of boku. He still uses watashi when talking to his uncle since it's the standard keigo pronoun.
Interesting enough, Fred switches from watashi to boku in Yaguchi's translation, signifying a shift in formality, more specifically when inviting Scrooge to their own home, he and his girlfriend.
Fred universally uses anata and ojisan - an honorific if common version of "uncle." Whereas in his informal circumstances, except for Shibaji, Benibara and Hataya, uses kimi, the informal second person singular that has a nuance of "pal/mate/friend" as in colloquial English. Benibara has Fred use the kanji 貴下 (kika, "you, young gentleman/lady") for anata - very much tongue-in-cheek to his much more senior uncle.
Thus far all except for the three, Shibaji, Benibara and Hataya, reflect the youthful spirit of Fred, whereas the former three render him somewhat more formal than what is intended in Dickens' original version.
Notable features include:
Benibara has Fred use the archaic -mousu (-申す) kenjogo verbal forms, e.g. omanekimousu (お招き申す, to humbly present an invitation), such as when Fred invites Scrooge to his own home to celebrate Christmas. This is essentially a manner akin to -masu from teineigo, i.e. the decorous copula. The only place where -mousu endings roam in contemporary Japan are films set in in ancient Edo.
Hataya makes Fred use shibuzura wo serareru (澁面をせられる, the sir/madam renders a sullen countenance) for when he remarks that Scrooge has no right to look so gloomy and dismal. Serareru (せられる) is a hyper-formal sonkeigo way of rendering the usual operative verb suru into a passive tense.
Old Jacob Marley is coeval with Scrooge and his business associate, thus it stands to reason that he should share some of his linguistic traits as well as a good manner of ominous and archaic diction considering that he lumbered his way from the Stygian regions of the dead - replete with chains, moaning and the role as the harbinger of three ghostly visitations.
In terms of the first person pronoun there is wide variety:
Boku (僕, "I, the young male") is wholly used by Yaguchi (1915), when Marley is talking in a non-aggressive way to reflect his more meek nature, but also when he is issuing the warning of the ghostly visits and that Scrooge must take heed of them.
Ore (俺・おれ, "I, the assertive man") is chosen by Yaguchi (1915), Hataya (1925), Hori (1928), Yamanaka (1941) and Yamamoto (1948). These are used in most cases to stress his nature that is akin to Scrooge, that of an ossified businessman, but in a ghostly reflection.
Ware (我・我れ・吾, "I, the ancient being") is also used by Kusano when Marley proclaims his warning towards Scrooge and announces the ghostly hauntings that shall teach him to be good.
Washi (私・わし, "I, the old man") is opted for by Kusano (1902), Benibara (1911) and Nakajima (1920).
Watashi (私, "I, the formal, adult male") is used by Kusano (1902), Benibara (1911), Hataya (1925), Hori (1928), Morita (1929) and Yamanaka (1941), all of which to project Marley as both a man of business, but also given the solemn/formal nature of watashi, an admonishing character - though he does not change to ware in the majority of the translations.
Plural pronouns are rare in these translations, but those that do appear are:
wareware (われわれ) by Yaguchi (1915), warera (吾等) by Kusano (1902), orera (俺ら) by Yamanaka (1941) and oretachi (おれたち) by Yamamoto, whereof the two last are various plural-forms of ore, though the former is the more rough one with -ra as its suffix, these in turn convey the dual informal sense of "me and you, Scrooge." The two first wareware and warera sound ever so formal and fit the personality of Marley.
Coupled with these are omae (お前・汝・おまへ), the informal second person pronoun that acts as a rather informal and assertive mode of speech, notably Benibara, at times, uses 汝 to write the pronoun where it in normal circumstances has the pronunciation nanji, the equivalent of a Biblical "thou." Thus Marley is referring to Scrooge with an Old Japanese pronoun that grants it ancient force, but pronounces it as the colloquial direct pronoun omae, instead - Kusano however keeps nanji as is and thus coupled with ware it renders Marley into an eldritch spectre.
Hataya (1925), Hori (1928) and Morita (1929) all have Marley use omaesan (お前さん, "you, good sir/madam), a more polite if rural version of omae - that at the same time sounds old-timey and reflects his age, since Scrooge also reciprocates in some by cases by using the same pronoun.
Hataya (1925), Yamanaka (1941) and Yamamoto (1948) has him use kimi (君, "you, friend/mate/pal"), an informal less assertive second person pronoun to communicate a more amiable tone, but Yamanaka and Hataya have him switch to omae, when Marley becomes ominous.
Even more decorous has Hori (1925) with Marley using anata (貴方, "you, dear sir/madam"), the standard gender-neutral second person singular, that is the most polite of contemporary pronouns, he does switch over to omaesan after his introduction - presumably to illicit an air of mystery to Marley when he first arrives.
Marley uses iru and rarely oru, the first being the standard way of saying "to be" and the second the generic geriatric manner. They also end their sentences in a rather standard male way, i.e. da, but only Kusano (1902) and Benibar (1911) have him use ja (ぢゃ), the Hiroshima dialectal way for old people to speak. Only Benibara has Marley use the polite, if archaic gozaru (厶る), an honorific form of "to be," spelled here with an equally rare kanji, that normally means "I/me", but is seldom used - thus lending Marley further an ancient if courteous air, along with the 汝 read as omae.
Both Benibara and Kusano use zoya (ぞや) as his emphatic particles at the end that give it almost the meaning of "gadzooks", whereas other merely use ne, yo, na and zo, normal ways of stressing surprise, friendliness or anger in the sentences.
The case of "Man of the worldly mind!"
Marley imprecates Scrooge for his lack of charity, ignorance of things beyond this world and knowing his place in the grander scheme of cosmos. How, then, do the translators handle his imprecations?
Man of the worldly mind:
Shabaki no ooi Sukuruuji
"Oh Scrooge, thou of plentiful worldly thoughts"
It is worth noting that 1) Scrooge is written throughout Kusano's translation with kanji meaning "this Luddite oldster", i.e. 固陋 means "sticking to old ideas," but pronounced as one would the English name. 娑婆 (shaba) refers to the idea of the "corrupt world" as seen from a Buddhist lens. 氣 (ki) can also mean character/spirit/mind/nature.
Shaba konjou no ningen
"Human of worldly grit"
Once again shaba recurs, but konjou that also means "disposition/character/guts" has with its many meanings ways of referring to Scrooge being gutsy and stubborn. Ningen whilst in modern terms meaning Homo sapiens, also stems from Buddhism to literally refer to the world of man, or humans as fleeting beings themselves.
俗人 if breaking it up means "worldliness" and "person", but is translated as "worlding" meaning "a person engrossed in the modern world," though here referring to the transient being of man. 奴 (me) is normally pronounced as "yatsu" (guy), but can be pronounced as the imprecating suffix me that denotes meanings such as "damned/fucking/wretched."
Awarena jinkai no ningen
"Pitiable human of this fleeting world"
The Buddhist terminology strikes again, with jinkai lit. "world of dust," but also "drab world," refers to this impure/fleeting world that like particles of dust will pass.
"Wretched creature of greed."
Yoku can variously refer to "greed/avarice" and even "want." It is also used as a suffix for words denoting excessive craving such as: donyaku (貪欲, "covetousness"), inyoku (淫欲, "lust"), gayoku (我欲, "selfishness"), juuyoku (獣欲, "carnal/animal desires") and jinyoku (人欲, "human passions/cravings). Thus old Jacob is not exactly holding back towards his dear chum in terms of writing out Scrooge's foibles. The suffix butsu is usually applied to objects or creatures, so Scrooge is debased twice: once in terms of being reminded of his cravings, but twice in terms of now being nothing, but a creature of them.
Where "prthhag-jana" stems from Buddhism to refer to an unenlightened person, someone who has not yet fully grasped the teachings of Buddha, and as such Scrooge is being called ignorant by Marley - not so much for being a greedy git, but being deprived of that thing called "being nice at Christmas."
Seken no yoku ni me no kurareta otoko
"Man lost with his eyes upon worldly wants."
As verbose as Nakajima, but more literal in terms of conveying Scrooge's incessant focus on worldly goods and the here-and-now, rather than thinking of others. 世間 can also mean more literally "this world of humans" (as in mortal/fleeting beings), and as such in a way related to ningen (人間, "human").
Indeed. Yamanaka's translation is more of an abridged adaptation for children, rather than a faithful translation, thus terms that refer to culturally specific things and references to western religion are generally either left out or simplified. This has, however, not stopped any of the other translators of taking terms from Buddhism to fit the message of Scrooge being an ephemeral miserly speck of dust.
Gesu na otoko
Whereas the other Marleys at least were ominous and archaic in their diction, this one outright calls Scrooge a git - indeed, 下司 can also mean a "sleazebag, boor, churl" and thus "git" fits the bill, as well. It anciently referred to anyone of a lower, menial rank as compared to the upper-class - such as Marley being a member of the higher echelons of business society and therefore - his ghostly status notwithstanding - entitled to berate and call his friend, a low-life git. Harsh and snobbish, perhaps, but as a upper-class twit, he is apparently his right.