Where did you find the info that the TTFone uses a fork - XDA? Possibly it can take CFW?
It's a de-googled Android hence AOSP and the source code is nowhere to be found, as far as I can tell. That said, I don't really know where they wrote the device-specific changes, just guessed.
As for the 8020, it's obviously an unproven product at this stage so picking that at this stage is pretty much a gamble.