I am surprised if the Toyota compressor is not compatible as the engine installation is pretty much the same, here at the middle of the end of the world we often have to adapt bits from something else as parts are simply not available,
My GTM kit car build is intended to have a BL Mini as a donor car for parts, there are no Mini's here, so my Mini hubs are fitted 1.6 Carolla front discs and callipers on all 4 corners,
I wanted to fit an ac as we can have 45c temperatures, Mini's were never factory fitted with ac, I'm not sure what my compressor is off, but it is compact and just squeezes in above the alternator with an adapted pully and its own drive belt.
John