Re the situation of IqAF in 2003: according to Tom Cooper's book Iraqi Fighters 1953-2003, no MiG-29s were operational in 2003 due to lack of spares. But there were one or more squadrons of each MiG-21/F-7, MiG-23, Mirage F1, MiG-25, Su-22, Su-25 still operational, the totals were of course very low. Btw, there were no defections if IqAF aircraft in 1991, they were ORDERED by saddam to go to Iran.
Since this is an AHC, i would start with a POD in 1991, namley Saddam i guess has a change of heart and decides not to send 120 of his aircraft to Iran, but try to preserve them inside the country. Some will be destroyed or damaged on the ground, but judging by the ratios of losses versus totals, a good part will survive. They could try a few more hits and run mission against the american strikes with the interceptors and shoot down a few more american aircraft, thus boosting morale and image of the AF, AND boosting the image of soviet/russian aircraft in the process. Same into the 1990s, with more aircraft remaining they might get a couple of kills against american aircraft enforcing the NFZ. Saddam might make a determined effort to get a handful of new interceptors and spares for the remaining ones, maybe he will manage to bribe some ex-soviet republic officials for some MiG-29s, Su-27s, S-300 etc. and smuggled through Iran (at a hefty price of course, like the iranians keeping half of those fighters and SAMs or something - since the IqAF aircraft were not evacuated and the iranians refusing to hand them back relations might be slightly better).
So when the americans finally get on with their plan to "liberate and bring democracy" to Iraq in 2003, Saddam might order an AF in a bit better condition, with a squadron or so of modern MiG-29 and Su-27 each, plus the remaining MiG-25, MiG-23, Mirages etc. to put up resistance against the americans. Sure, they can't possibly do any significant damage, but they might cause embarassment for the americans by shooting down some of their aircraft/helos, some ground attacks sorties against the american troops, maybe even some daring attacks against airfields within range (iirc in OTL in 2003 they planned to have some Mirage F1s to attack an objective, can't recall what it was, but it was abandoned at the last minute because of an accident).