First, I understand ED's point bringing existing aircraft to FC4, because the development will be pretty easy. The FM and the 3D model can be reused. Making other plane like Su-17 or even F-22 would require a complete new AFM and new 3D model for each of the four planes - maybe that might not be worth it. If they have very low production costs for FC4 and only new players will buy FC4 it can be worth it.
I am pretty sure ED knows that people who already own a full fidelity module won't buy the simplified one.
Second, I don't think there will be simplified planes of any 3rd party devs in FC4, maybe except from Belsimtek.
So the list of possible planes narrow to the following one (in my mind):
ED: A-10C, KA-50, L-39, maybe F/A-18C and why not one of the WWII planes Spitfire, Bf109, FW-190 and P-51
Belsimtek: F-86, MiG-15, F-5, UH-1 and Mi-8
Maybe the planes in FC4 are a mixture, like FW-190, KA-50, F-5 and L-39