Actually Final Fantasy Adventure (Mana), the Legend series (actually SaGa), and Vagrant Story also have full coverage on the FF Wiki, so I wouldn't necessarily call it evidence.
BD is pretty much an FF in all but name, but I prefer to think of it as a separate IP that has grown away from the source material much like Mana and SaGa have from FF. Also Chrono Trigger has more in common with DQ than FF if you ask me.