Someone suggesting Ike moving up to C rank makes me sad. He should maybe be above Falco. The Ike boards talked about Ike's recovery VS Falco's recovery a while back. Falco falls faster then Ike, and is dead if he has to use Fire Bird. Ike is dead 95% of the time if he uses Quick Draw, but never has to use it as long as he still has his second jump. The other 5% of the time is very unique situations such as if Marth has countered Aether once, drops down to intercept the next one, but Ike got knocked high enough to QD onto the stage while Marth is down below. The difference between these characters' two bad recovery moves is that there are a lot more situations where Fire Bird would be required then there would be situations where QD would be needed. (Falco has no other way to recover if his DJ doesn't get him high enough, as long as Ike still has his DJ, he can cover the QD distance)
Illusion is a highly upgraded version of QD (or QD is a heavily nerfed version of illusion, however you wish to see it), but it still suffers some of the same weaknesses as QD, just not nearly to the same extent. If Falco has to shoot for the ledge, someone could edgehug it, or intercept with a fast enough attack, but is otherwise fairly safe due to it's speed. Aether is safe against people who lack disjointed attacks, but gets eaten alive by the likes of Marth's counter, or something like another Ike's Ftilt. Aether can also be edgehugged, but would require stricter timing due to the duration of the move. Both moves are spikes, but Aether's is much stronger and can pull people off of the ledge. Illusion is overall safer, but less threatening to the opponent.
Distance wise, I'm not sure which beats which. A fully charged QD would probably beat Illusion, but how often does that happen? Aether and Fire Bird would be fairly close in distance vertically. QD can hold a charge in the hopes the opponent messes up his timing, Fire Bird has more horizontal potential then Aether (at the cost of some vertical).
Overall, Fire Bird's complete helplessness and the fact there are situations where it's required bumps Falco, IMO, below Ike in recovery.