The answer to your overarching question is yes. The problem is you have to know the numbers under the hood. Each position has a relative "strength" or "importance" level, whatever they call it. This number, if I have understood correctly, drives the difficulty to obtain the position (longer denial window or your hub moves more slowly obtaining the position relative to a more simple option available.)
So yeah, all back mount variations should be the most dominant positions to finish a submission. My guess is, if I'm correct, a RNC from seated back mount should have much faster gates than a brabo (darce) choke from half guard or sprawl (even if both at equal * moves).
This answer is me deducing logic from GPD's initial grappling tutorial that was posted on here months ago. I could certainly be wrong. I also don't know how smart this game is.
Example is be curious to know how variable this game is:
- RNC from back should be super strong (fast gates) for Maia relative to arm triangle from mount. On the other hand, perhaps arm triangle from mount may be stronger for Jacare than RNC from the back (even if all submissions mentioned are 2* moves). This part, I doubt exists. I would assume the game has placed a universal "position value" this is applied in a blanket fashion to all characters and simply interacts with their stats, GA etc. from that point on