Anything specifically required, besides a bachelors degree, in order to transition branches and commission in the Army as an FA?

There's no guarantee what branch you'll get. You'll have to go to OCS, the Army doesn't do direct commissions except for JAG, chaplain, and medical.

Not that it esp. matters other than purely out of interest, I'd just wondered, how did you happen to settle on wanting FA? It's obviously fine, of course, certainly, I merely found your specific interest in that explicit branch interesting, that was all, if you might care to elaborate on that aspect at all...also, have you gone masters or Ph.D. level yet at all, or given any thought to that? I only ask, as, I can assure you as well, all services, for all warrants and commissioned, will virtually automatically insist on your getting, minimum, a masters, virtually from day one, trust me, been there, done that (BTDT)...as I'd said, you being USAF enlisted will obviously help you considerably, I'd just be most eager to hear more, as I found your specific question and preference of quite genuine interest, as I'd said, I hope all that was of use, if I find anything else I was thinking might be of similar interest, I'll try to send that, as well, OK?

https://en.wikipedia.org/wiki/Naval_Postgraduate_School

The same is true for this one for Navy...when I'd been in, my USAF CO O-6, he'd made O-7, I didn't know him at that point, had given me a recommend for my masters here, I couldn't get it, you might find their online Ph.D. in systems science of interest, it's the only one of its type I'd ever seen, as with AFIT, all warrants and/or commissioned can apply, senior enlisted, I'd only seen for USAF for AFIT, there was a YouTube video on that, NPS, I don't know if they allow it analogously, you'd probably have to do at least a couple of tours as Army commissioned to have a serious chance at either school, you wouldn't need to go interservice, Army can go to both, it's just that Army, aside from the command and general staff and war colleges, has, from what I'd seen, nothing analogous to AFIT and NPS, that was why I figured you might find knowing more of them of use and/or interest....