In my game i’ve made a player controller drom scratch, but I don’t want to sue this in certain level of the game, I want to use a total different controller (i made from scratch too). But only for one level, and then revert back. (sorry for my bad english).
it is called game modes, i’m sure you know what game mode is to reach the point of creating several controllers. But you might don’t know that you can toggle it at any moment of the game, or at any level.
So in the level you want to have unique controller, open the level, choose the world settings from the right side panel, and override the game mode or just replace the controller 
try this solution as well, i posted a while ago:
-m
Thanks again,may i reach you over skype? i saw you put it public in the forums.
go ahead please 
-m