AOSP isn't dead, but Google just landed a huge blow to custom ROM developers
(www.androidauthority.com)
The trap: He could stop builds for the OP7... tomorrow with zero warning.
That leads to my main takeaway for custom roms. Pick the phone with the most topics and replies on XDA. The more popular and liked, the more supported you'll be.
and never get attached to anything. Your phone miraculously has support, none are guaranteed it.