Public IP address assignment to the CPE as well as billing

I am a new WISP and we had already planned to use Ubiquiti setup. Since challenges of NLOS we had to look for LTE solution. Question I have our plan was to use Ubiquiti routers and have it set up to where each CPE at the residence would be issued a public IP address. I’ve already secured class C adressing to be able to issue these.
Surely I can also do this to the CPE of Baicells?
The radios and the CPS would I have all internal IP addressing and the routers would know any traffic coming from that specific CPE is Nat to the public IP address that would be assigned.
Regardless of what the client may try to attach behind the CPE I would then still be able to trace down any copyright infringement that I may be provided for my carriers.
The next question I have is I had planned on using Ubiquiti Aircubes for the indoor client connection point.
by having that device I would then be able to use Ubiquiti UNMs system for the billing.
I was curious what others are using inside the residence as the meet me point to the Baicells gear.
My final question is if I do not use the Ubiquiti unms system for billing what has you all success been with coplex.