I think some of the rules I posted are different than the rules when my babe was born. They are (on paper anyway) being far more aggresive about forcing you to come to the military hospital. I expect there are ways around that. You could try to find out what the borders of the "military hospital catchment area" is and make a point of living outside them. Or at least have an address of record outside them.

My understanding (and if this isn't on point to your question, tell me) is that Prime is like an HMO: You use our facilities, our docs, period. Like Kaiser or something. Standard is more like a PPO: Here is the list of our docs, if you go to them we pay X% with a Y deductable, if you go off the list you pay a higher % and a higher deduct but we will pay. So based on that, if you go Standard they should pay any licensed medical provider. But like I mentioned, they are trying like crazy to herd all us brood mares into the military corral, so they keep throwing up additional roadblocks.
Let's do this, we'll ask around here and maybe you can ask around among military families you know in person if anyone is on Standard and see if we are understanding correctly how it works.