This might not be what you want to hear, but you're wasting your time. I have been there. Every one of these fucking android foans has its own foan-specific modifications to the kernel which can be found nowhere else, and not in a good way. You will need to be familiar with these modifications. Then, there are the userspace device drivers. Yes. Userspace device drivers. Android has them. Much of the hardware on your foan will not work without them. You will need to be familiar with every bit of hardware on your foan that you want to get working. These bits really add up. Camera (front and back), wifi, modem, audio, bluetooth, charging (yes, often a foan will not charge without drivers for the foan's power manager), accelerometer, magnetometer, storage (onboard and sdcard), video, touch, etc.. If you want your port to become official, that extends to literally every bit of hardware on the foan, period.
It will take weeks of real time to learn the Android operating system and to finish porting an unsupported foan, and when you're done, there will be like three people globally who will use your work. Your foan is one of literally hundreds of other android foans that are all just as (un)popular and that all require the same amount of work to port.
But above all, android does not deserve your time, nor does it deserve anybody else's. The development end of the android operating system is a terror to look upon. Just to compile it requires hundreds of gigs of SSD hard disk space and about 20 gigs of RAM. It deserves to be burned to the ground.
Take that time, convert it into legal tender, and use that money to buy one of the phones that the opensource community has agreed to support—a fairphone if you want something androidous and worky, and a pinephone if you're feeling adventurous and want to see what the opensource phone world looks like without android (preview: quite a lot nicer on the development side, still a little broken but definitely usable on the user side).