I heard some people changed their router name to "bestbuy" during Streetpass weekend. I was wondering if this works for Nintendo Zone items as well. Also, I have the capability to set up a phone hotspot. Would that work?
Literally any SSID that are associated with Nintendo Zone allows ACNL to receive Nintendo Zone items. Some places can also offer items exclusive to some NZ hotspots.
As for the phone acting as a wireless hotspot, I believe that it depends on the phone itself. I'm pretty sure you have to try it out. If you can at least use a specific SSID, you can access to Nintendo Zone content, but not StreetPasses. For that latter, you will need to set up a MAC Address that matches with one of the Nintendo Zone hotspots.
I'll give you a few links that will help you out on setting up a home StreetPass Relay for more details.