Hi @Millertime3900, Thank you for reaching out and welcome to the community. Thanks for letting us know the situation you have for your Sonos system. To answer your questions.

• It may or may not work for setting up speakers through Mobile Hotspot. You may check this article about Sonos system requirements for further information. 
• It would be best if you had a High speed wired internet connection such as cable, fiber, or DSL since these are the recommended set up for Sonos speakers. 
• Yes, it would help if you had an active internet connection for the Airplay 2 to work.  You may check this article about Sonos App requirements for further information.

Recommendations would be having a wired internet connection such as cable, fiber, or DSL for the Sonos speakers to be successfully set up and work properly without any delay or dropouts since that is the recommended setup for Sonos speakers. We can wait for any recommendations or suggestions from other Sonos community users about their experience and thoughts for this kind of setup. 

If you have other questions with your Sonos products, feel free to reach out.

The Sonos community is always here to help. 

You only need Internet for setup and updates, and for making some settings changes. But you do need a local network. 

A hotspot may well provide what you want. You should also consider a travel router, which can use one of your mobile devices for an Internet connection, but may give you a better LAN. Or you could get a 4G router with its own SIM card.