I have got an MX64 security appliance and a couple of MR32 WAPs at a small office. Unfortunately the DMarc where my main and backup the Internet connection comes in got damage so my Internet will be out for several weeks.
I thought I would go to Verizon, Sprint, or AT&T and pick up one of the compatible USB 4G modems, but none of the companies stock them at the store. Also, they cannot guarantee that the versions they special order will match the USB IDs on this list:
Is there any way I can bridge one of those Verizon MiFi hotspots to the MR32s to get Internet access at that site?
If you have a spare laptop, you could connect it to your hotspot.
Then configure the internet connection to be shared, connect it to the laptop via a unmanaged switch (or etc).
Then the MX and devices would use the laptops shared internet connection via the hotspot and come online.
When I was having ISP problem, I connected a Verizon JetPack to a laptop, and I bridged the JetPack and the laptop's NIC card. Then, connected from laptop to the Meraki.
I didn't have good experience with this setup. May be a USB modem will work, I used this Verizon Global Modem USB730L
Verified this device below works on MX64 and others on T-Mobile with minimal setup. Might be a solution for you.