Hi Davy,
Nice to hear something from you! I hope everything is alright.
If I am allowed to give you a suggestion about the development of Polyphone: I think you can help people the most with extra information about soundfonts and its possibilities.
About the crossfading: creating loops remains a challenging thing anyway and one often needs an external audio editor for good audio samples. For the loops I presently rely on
Endless WAV from
Björn Bojahr.