I want to usb tether a 4g tablet to pepwave surf on the go and from there ethernet to xbox one. Is this possible or will there be follow up issues with IP or Nat settings on xbox
Depends on your cell provider. Some providers assign you a NATTed address, so port forwarding won’t work. If they assign a public IP, you shouldn’t have issues.
Since your internet link is wireless, you may have an easier time using the wifi hotspot on the tablet and connecting the Xbox wirelessly.
Good luck and happy gaming!