Chelle, I know you personally don't have the A3 but assume you have the A7 Prime.
Does the A7 Prime's built in hotspot activate on a non-VZ SIM card or it complains about an auth issue?
What about USB tether/RNDIS? Depending on the build you have, this might check if you're already connected to a USB data port so you might need to plug it into a laptop or something that has USB host enumeration on the other side of the cable.
Not a blocker for me but the provisioning override could be a hurdle to my less savvy neighbors as they would very much like a seamless experience.
Edit (Poorly written): From what I read, looks great. Certainly I want to get one for my kit (presently have several AC powered ones with custom firmware (e.g. tomato, dd-wrt) for traveling) and bridging LTE to my home router when my ISP goes down.
I don't know the upper limit, but everything in my house is connected to one.
4 Echo Dots
1 Google Home Mini
4 Fire TV Devices of various generations
1 TiVo Stream 4k
6 smart plugs
Printers, Wyze Cams, WatchAir Antenna, and a handful of other devices that I know I'm forgetting.
Usually only a couple of devices are in use at any one time but they all stay connected.
The only problem we've ever run into was that one of our two devices acted flaky until I turned down the WiFi "range" setting a little. No problems, since.
I just got the A3 Prime a couple weeks ago and MTK Engineering Mode doesn't work. I believe they released a new version of the A3 Prime.
When I click the MTK button, it says "Cannot find EngineerMode app. Mediatek chipset is mandatory and stock ROM must be installed."
I checked the app list, and EngineerMode is listed, but I can't access it. I've tried QuickShortcutMaker, and the * # * # 4636 # * # * dial sequence. Any ideas? I keep getting stuck on Band 13, which is no good :\
You may be helped by looking at the following thread on the ZTE Blade A 7 Prime which should likely apply to the A3. Installing the MTK Engineering Mode app(Monster) mentioned should give you access to MTK EM.