@rzwitserloot for some reason (perhaps my lack of reputation points) StackOverflow won't let me post this as a reply to your answer. So..

I take your points and your concerns. Obviously one praftfall that can happen here is that if I create a proxy that makes assumptions about methods with identical method signatures, and the library authors enhance their library by introducing new methods of that signature that do not ADHERE to my assumptions, I will have problems.

I intend to create a PR for this library that formalizes this interface with an actual interface. And if they accept that, I think the tactic of a workaround UNTIL my changes are released (and I update my dependency) is a low risk, valid approach.

I'm nothing but grateful for the effort and thought you put into your answer.