How can I setup mulitple MicroCell accounts?

You can setup mulitple MicroCell accounts on your myAT&T MicroCell Settings page (just give them different names) using the same phone number to register/activate the MicroCell.

Your phone number is not entered into the MicroCell per se. The MicroCell's serial number is associated with your account (post paid phone number). You could setup the second MicroCell at the same location that your current one is at and then move the MicroCell to its new location and then see if it will work (internet connection, GPS location, etc) but you can not remotely setup and activate it because your phone needs to be within range to register the MicroCell as being part of its cellular neighborhood. There are no hacks for the MicroCell as it is a totally closed system.

That being said, WiFi-C is what AT&T and us recommend now if your phone is capable. AT&T stopped selling the MicroCell's at the end of 2017 because the MicroCell had reached its EOL. Service will continue through this year until AT&T begins to transition away from their 3G network, probably around Feb. 2021 or sooner. At that point in time the MicroCell service itself will discontinued as well.