Hmm ok so that could be either #1 or #2. I'll try and take a crack at my logic for determining which images to load to something that doesn't depend upon the compositing so if that has issues, it still only loads the necessary ones, and i'll test it out with 0.5.20a. Probably won't get to it till the weekend as next few days are busy.
I'll also probably take a crack at a really efficient design that uses a smaller number of button objects and re-uses them. Dealt with some similar designs for web pages, though doing the asynchronous loading in Godot will be a lot more painful than it is in javascript.