Why? Unless we're starting a fanfic, this can remain here. Theories can go in Land of the Dead, as far as I know.
I think Eva remained with the LSA, maybe even took over after Salvador. Having Hector gone is not necessarily going to change much of Nuevo Marrow as he probably had a lot of followers. LSA is still going to be needed, though it's possible that they wouldn't have to remain underground anymore.
Characters like Membrillo and Toto probably continued their afterlives as before. However, Lola's death probably affected Toto, at least a little. I would have liked to see a sign of that in the game, but it's good this way as well. The "Tell her papa Toto said hello" comment breaks my heart every time.
As for Maximino, I like to think that Olivia dumped him and that caused him to get depressed. That added to the fact that Nuevo Marrow was growing and casting Rubacava into a shadow probably made him a broken man no longer able to continue his business properly.