As for your ‘get all actors by class’ problem, this should do the trick:
My apologies for not going that far beforehand.
If you confirm your selection does it use the correct option, and just doesn’t highlight the option that is currently selected? I don’t know how this is set up so I can only make uneducated guesses, it seems to me like it should work though.
You could try to call the old function and check if that still works.