You can only truly represent what the F35 is capable of and what other fifth generation and other fourth generation aeroplanes are capable of when you have all of the classified information.
That statement would certainly seem to undercut the validity of any effort to simulate JSF-versus-anything-Russian-or-Chinese, would it not? One side of these sims is always open-source intel + common sense analysis. Why should such techniques not work in both directions?
Backing up a little to the 1-v-2-seats: I believe that the FAF, who at one point planned to take most of their Rafales with two seats, have not gone as far as intended in that direction, and indeed if you look at pix related to the Mali op you'll see lots of single-seaters loaded to the walls with LGBs, AASMs and pods.
On the other hand, I also believe that the USN has loaded its Block 2 Shornet buys heavily with the station wagon model and of course the RAAF has bought only Fs. The USN has certainly made a big deal of two seats in the FAC-A role and the ability to have the nose gunner
focus on the sky and the GIB on the ground. One argument is that although automation has improved the sensors have become more capable and there is a bigger picture to comprehend.
There's probably little point in a two-seat JSF, though - it is indeed highly automated, so the back-seater can do little except watch as the sensor-fusion gizmo puts on its wizard hat and separates the righteous from the ungodly, without explaining how it does that because it is secret.