Wireless Joint

Here's the list of everything of what I have:

1) Dell Optiplex 755 (Running Windows 10)
2) Sprint Mifi 8000 (USB Modem)
3) 45dbi 4G LTE Mimo Antenna (2-meter cables)
4) TP-Link Archer C7 AC1750 (V2 Router) (Running the latest Goldenorb)
5) 2 Remo 15dbi Dual Band Wifi Antennas' (15ft long cables)
6) 1 (Black Slimline-Type) Dish Satellite (Primary Wifi Antenna installed going one way.)
7) 1 DirecTV Grey Satellite (Backup Wifi Antenna installed going the opposite way.)

Now here's my questions....

1) How to connect the mifi via usb to the router after firmware install?
2) How to find out what bands I'm currently using in which how can I set up band lock from the router? (B2, B4, B12, B25, B26, B41, and B66 is the closest Sprint and T-mobile towers near my home of what I've found via cellmapper but I think I can connect to atleast 5 of the 7 combined bands when the mifi is connected to the router).
3) How to tune and set up the router to correspond with both dual band antennas for the purpose of Long Range Wifi Internet?
4) How to set up load balancing with all of the combined Internet sourced connections with failover?
5) How to get the most power, performance and efficiency from this?

1. If the MiFi 8000 had an ethernet port, that would have been the easiest and most reliable way to connect it to any router. Having only a USB port, the big question is whether the router (OpenWRT/GoldenOrb/WiFix) has the proper drivers built in, you'll just have to try it. If not, you could still tether it to the router via WiFi with some speed degradation and slightly higher latency (the more wireless hops, the higher). Even then you will likely not be able to put the MiFi into passthrough mode due to its locked firmware, creating issues with DHCP, and port forwarding.... in other words, "No bueno!" ;D

2. You will not be able to set the bands from the router, and probably not even on the MiFi either due to its locked firmware. You could search to see if there's a backdoor way through SSH. A better option would be to use a modem in an external USB enclosure connected to the router's usb port, which would allow full control of band locking, etc. You could also use a cheap WE826/WG3526 router as a modem enclosure in bypass mode.

3. Use a wide band flat panel or Yagi WiFi antenna which should cover both 2G/5G bands. If the range is not enough, you could add a long range WiFi amplifier/repeater.

4. You could use the MWAN3 load balancing/failover feature built into OpenWRT. For channel bonding (combining speed) you could use OpenMPTCPRouter (https://wirelessjoint.com/viewtopic.php?f=21&t=1078). Besides the MiFi what's your other internet source?

5. Your power/performance/efficiency will only be as good as the equipment used. The TP-Link Archer C7 is fine, but you may want to reconsider your choice of the MiFi/modem.

Good luck!