As Amiga is a registred trademark I would suggest to call the project something else for now.
Btw. a name for the motherboard isn't really important, the fact that AOS4 and Linux is fully supported is.
Guess the project stil needs a name :) How about calling it AG5, A-G5 or something, atleast the A would indicate it was an Amiga (like A-1200) but not brake any trademarks (I think).