Thanks for this really useful extension. I'm in the process of adding it to the extension directory and noticed some "unusual" behaviour.
It seems that the majority of the blocks take HEX values for the colours, but two of your methods expect standard Thunkable colour blocks:
Would you consider renaming these two methods? Perhaps
ChangeColorBG3 could be
ChangeColorRGBa and instead of
ChangeColorBG2 it could be something along the lines of
MixRGBColors since this would better describe what they actually do?