GPL . really ??? not even MIT … I stand corrected , that changes everything. I was not aware of that. Well if its GPL based even partly that is more than worthy for my trust.
I dont close the door to the idea of embeding CSOUND for LMMS will keep an eye because I am very interested in working with CSOUND at C++ level too even outside LMMS. I dont doubt that it may work on Windows, thats the nice thing about Windows is hands down the most dev friendly platform. No coincidence that it dominated software for so many decades.
Will take also a more careful look to JUCE you peaked my interest. A lot to learn