When you say backup, what exactly was running on this image? Doesn't seem to be ATT. Can you be really specific?
I was able to swap my IMEI and restore calling and data but only on this Firmware, but i'm limited to 4G LTE and no VOLTE and I can't seem to use any other firmware. If I flash back to stock KDZ my device becomes network locked.
UPDATE: I fixed everything now from scratch Zero now after wiping my entire flash, including IMEI and T-Mobile Stock and Network Lock. I am happy now.