I've just successfully compiled blisspop lollipop ROM with pexcn sources (very simmilar to marvollo's rom). I have no much knowledge about developing but if you need any help I'm here.
And those libraries aren't updated on latest Mi2S roms? They can be extracted easily from the MIUI ROM and added to vendor_xiaomi_aries to compiling the ROM with them.
He is the developer that is porting multirom to our device. In xda-developers forum his nick is dnv_aps
Have you tried installing ROM with twrp version provided by the dev? Maybe it's needed for right installation.