[Q] Using Verizon sim in Router topic

I have 2 questions:

1. What's a good router that takes a Verizon 4G sim card?

2. Is there any way to swap unlimited data between 2 cell phone numbers? For instance, my mom has unlimited on her line, but she only uses ~1.2GB per month, would it be possible to transfer her unlimited to another line, use that SIM for the router and her retain the same cell number?

Thank you.