ToT on AESA is NOT Happening. HAL will get the radars and they would put them on the aircraft with guidance from the US sources. This is the way things have been done with the Turks and Scandinavian countries and I see nothing exceptional being done here for the Indians...I think some of our Indian friends are getting a bit carried away by the US offer.
Having stated the above, IAF can, like PAF absorb US aircraft. It will take some more time but again its not out of question as they have always flown European aircraft if not American.
F/A-18 would be a threat greater than the Su-30MKI simply owing to the fact that serviceability on the Super Hornets would be much higher than the MKI and the Hornets are a much more proven MR platform than the MKIs. In WVR, F-16s are equal or better than the F/A-18s and with JHMCS on both, it would be about equal.
In the BVR arena, if IAF receives AIM-120Ds, PAF by that time would also have the same or even before the IAF receives them for as long as the relations stay as they are between Pakistan and the US.
On a side note, IAF really have no idea what a difference an American aircraft would make. They are singing praises about the MKI now, but if either the F-16 or the Super Hornet was inducted in the IAF, they would start looking at the Russian aircraft a bit differently after appreciating the serviceability, support and capability of the US aircraft. Without a doubt, US aircraft are a better bang for the buck in the long run.
PAF knows this well thus will be worried about the induction of the F/A-18 within the IAF.