Losman. Not because they think he’s better, but because they need to give him his “opportunity” and there is no reason to risk injury to Edwards since their season was toast since week 5.
NE clinched today, so it wouldn’t matter what the Bills did they had no chance of sniffing the playoffs without taking the division (that went for any AFC East team).
If Losman does have one more year on his contract (?), they would play him out so they can generate whatever trade value they can. They will probably trade him during the draft for some picks or to move them up.