@aldburg I'm playing the waiting game too. April 15th is the deadline and want to know for sure on GEM opportunities whether University or Associate Fellowship. GEM seems unresponsive when I ask they have just said they'll update us on what to do after companies have made their decisions if we weren't offered a Full Fellowship.
I am in no way the person to trust 100% but I say while you wait to hear back from GEM you try to get in contact with the GEM representative at the school for your MS and see if they know anything of possibilities of funding. Some people have mentioned this has been successful for them and that some schools are not able to because their budget has been planned, only provide funding for Full Fellows, etc. See if they have any input.
Also, I guess the more important decision would be deciding which track you would want to take. Those are two very different paths and that life decision is up to you. Depends on how much financial aid is important to you. If you would hands down choose the MS program if you received full tuition then I would say go with that one. Regardless, contact who you can before April 14th and if nothing of substance comes back then make the decision. I'm not sure how difficult/frowned upon it is to back out of accepting a PhD offer, obviously try not to.
A lot of people have April 15th deadline so hopefully GEM takes this into account and gives us an actual update before then.