I think a telling measure of the Yak-7's performance is that the 109F-4 is inarguably the superior of the two. Its faster at all altitudes, climbs better, has more ammunition, and has more flight time. Its also pretty maneuverable.
IMO, the only chance the Allies have is vulching the He-111's on landing and takeoff. I haven't read the specifics for the He-111, but if they can fly at any reasonable altitude, any escort will be highly effective.