Short answer to all questions is, YES.
I have one AP with SSID that covers both 2.4GHz & 5GHz, I have a guest SSID that covers only 2.4GHz with bandwidth limits & I have a separate SSIDs for 2.4GHz & 5Ghz.
The configuration possibilities with signal sources available from Ethernet, cellular or WiFi are really pretty
interesting & limited only by your imagination.
Do I need, or actively use, all of the above? NO, but, I’m trying to explore what works best to take advantage of what we have available at a given location.
Be aware, to my knowledge, this device has not yet been certified by Verizon. There are work a rounds & once activated on the Verizon network it works very well. I’ve activated two of them so far with Verizon & the process (my experience ) would best be described as very time consuming & frustrating. However, even with the crappy experience with Verizon, I love this unit & would have no problem recommending it.
Search CAT 18 certification on this forum for info on issue.
If it’s OK with the forum, I’ll give a plug for the vendor where I purchased mine. mobilemusthave.com. See if you can schedule a pre-sale consultation with them & let them know what you are trying to accomplish. They were more than helpful prior to & after the sale.