Will anyone get on board?
Aside from personal feelings about the idea of FF and Linux phones, I'd query that the big manufacturers will want to be producing handsets on such a wide range of OS. You want your preferred OS on a decent, competitive handset and surely you're not going to get Samsung releasing the same handset with a choice of OS?
Hell, manufacturers aren't even that interested in WindowsPhone - so are we going to rely on some dedicated company making phones for these bit player OS?
How is it planned to play out? Not an attack on FFOS I'll save that for another thread!) but a genuine question.