SMPS Simulation Help
Using tips from both @a concerned citizen and @qrk I think I figured this out. I switched to LTSpice as it has a bunch of half bridge drivers already in the libraries and it just seemed easier to use. I went back and modeled the transformer as a coupled inductor with the leakage in series. This seemed to help some with the S1 current waveforms.
I used a GaN fet I already had modeled in spice and double checked the curves. I think the Q2 current wasn't showing up in Multisim due to the fact that I was driving it incorrectly. The PWM amplitude was 9.5v referenced to ground when it really needed to be referenced to the source of Q2. Using a half bridge driver fixed this. The LTSpice circuit looks like this:
The waveforms: