So I've been putting apps on this device and getting it all configured for when I give it to my mom on Christmas, and I can now report back with some answers to some of my questions:
Yes, the screen is glass.
No, it doesn't have Bluetooth.
As for memory cards, it takes MicroSD cards. I'd been confused by the fact that the manufacturer said it used "PH cards," but I understand now that a PH card is the same thing as a MicroSD card.
As off-brand Chinese tablets go, the Zenithink C71 Upgrade is pretty nice. My only complaints so far:
1. When I try to download Jeopardy! or Wheel of Fortune from the Play Store, I'm told this device is not compatible with those apps. I'm sure it could run those apps just fine, and it's simply being discriminated against because it's a gray market import nobody's ever heard of.
2. The screen refresh rate for things like pinch-to-zoom is not as fluid-looking as it is on my Samsung Galaxy S2. It still works just fine, but it's slightly clunky looking, as if you're watching an animation that's skipping a few frames. This tablet has a dual core 1Ghz processor vs. the Samsung's 1.5 Ghz dual core, and maybe it takes more processor cycles or memory to keep up with a seven inch screen, as opposed to a phone screen? This is a very minor complaint, though, and I doubt it will affect my mother's enjoyment of the device.
3. The official, paid version of Pac Man runs kind of slow on this device. This, coupled with the above complaint about screen refresh rate, leads me to believe that if gaming is your thing, you may want to spend a little more and get a more mainstream tablet with a quad core processor. On the other hand, it could just be that Pac Man was coded poorly. I do recall seeing in the Play Store that other people had similar complaints about it.