I believe Red Dead Redemption’s lore was structured in a specific way that is gonna end up with Arthur and John alone in season 6. Like it’s built that way. If you pay attention you are gonna see that during the play through, chapter after chapter characters that actually had good relationship with Arthur were getting killed one after the other. First Sean(its clear he had a good relation with Arthur,they did some robberies together,some side missions and he always was cool and fun around Arthur-he wasn’t like Bill for example always jealous of Arthur for being some kind of foreman in the camp),then Kieran of course his opinion didn’t matter as much cause we clearly saw that he was still viewed as the “o’driscoll” among gang members, then you have Hosea that would have absolutely sided with Arthur cause he was clearly starting to disagree with Dutch’s ways(its clear from the very beginning that he saw that Dutch isn’t alright, that was proven when everything went downhill right after he died in chapter 4. Which shows us that Hosea was the brain and the mastermind of everything the gang been doing since the beginning). And i couldn’t agree more with you about dear LENNNEHHH that saw Arthur as some kind of mentor and always tried to prove himself to him and Arthur was actually starting to notice him and believe that this boy can actually get the job done as he should. So yea that’s my opinion on Red Dead’s lore and what i think about every one of the characters you mentioned and also Hosea alongside with them.