The following are other efforts in creating simulators that can be useful.
Synthesis by Autodesk
The most advanced robotics simulator and it's open-sourced. Optimized for FRC simulations, this one is most likelly to be the de-facto standard of FTC once someone decides to mod it for FTC use. They do have a Velocity-Vortex field, you can import robots from Autodesk and a whole bunch of other features. If you're looking to help the FTC community by suppporting a simulator, I recommend putting your efforts into this one.
FRC Sim 2016
This one appears to be abondonned, but if you want to contact the authors you may want to use this as a starting point.
FTC Team 12010 Relic Recovery Simulation
A unity project that the authors may donate to you if you ask. Also a good starting point.
FRC Field Sim
Another FRC simulator.