Yep, I liked it too! (Especially the shortcut route, that gave me serious Night Market vibes ^^)
I also thought the Samurai used a few somewhat uncommon words, but maybe they are just unknown to me 
Page 79 answer attempts
You translated this already as “reborn”, no? https://jisho.org/search/生まれ変わり
A (maybe) subtlety:
https://jisho.org/search/全うする - to carry out, to fulfill
(I think this makes more sense together with ために、maybe?)
Other than that, I think you got it pretty much:
“Rebirth as a human, to again try to fulfill a new life for the benefit of the world, but” (I take this to mean that he wants to be helpful to the world, to serve it in an abstract way, if that makes sense)
周りに止められた - I was stopped by the “people” around me / my environment (who were where his soul was chilling all this time)
And then he goes on to explain why they stopped him:
４００年も休んだ魂では時代が余りにも変わった現世でまともな人生を送れないかもしれないと
(you skipped a column here, see the bolded part)
時代が余りにも変わった - I think this is just saying that “the times” changed drastically
現世で - in the real world (i.e. from the world that he was used to before)
All together maybe “in the present world where the times have extremely changed (= are different)”
送れ - this should be the “to spend (time), to live one’s life” meaning?
From your skipped line 
this seems to be extremely plausible: “I can maybe not live a normal human life”
Yes, it is as if this gets inserted into the previous sentence, to explain it more:
周りに。。。と止められた
TL;DR: He was allowed to come to the current world and so he thought he would be reborn as a normal human, but “they” told him that he would probably not get along too well because his mindset is too far from the current world, and so [next pane:] he was sent to the current world as a ghost to get used to it.
)
No wonder I felt like the sentence was missing something. I knew it had “honest” or “upright” in there but it was gone when I made the post. 
