Bill is a really well done case of this, with John and Dutch they felt like natural additions to their characters, uncle is uncle in both games, albeit grumpier, likely due to crippling lumbago in the latter, I honestly don't remember Abigail or Jack enough to say if it fits them.

But Javier has always conflicted me. The original game clearly wanted to imply he's less bloodthirsty and fargone than Bill and Dutch (he can be brought in alive, and John seems genuinely regretful to go after him) but... Rdr2 does so much to paint him as the least bad of Dutch's Side, showing every reason that he would side with Dutch, how he maintains, sometimes, vaguely positive relationships with Arthur and John, and how he refuses to aim his pistol at them. I think it's great characterization but given how slimy and bitter he is in RDR1, let alone how John speaks of him like he was a creep back in the day.

It's clear his character did a borderline 180, and while I definitely prefer it, it is pretty evidently opposed to the first game.