Yes and No.

Open source for the kernel is essential but unless you have a full android build tree for it is quite difficult to implement the HAL needed for SFOS to operate with all features.
It is possible but you'd have to do a lot of work yourself to make it happen.

Libhybris as it exists implements the HAL on top of the android driver layer which normally is taken from an existing CM release for the device. All the stemps to build it are fairly well automated and documented which means it is doable without deep knowledge of the devices innards.