Actually, I got this one resolved! Turns out there was a more recent firmware just for the 7545 and 7556. Installed it and everything is straightned out!
The errors don't make sense for the jobs obviously, and it isn't corruption because you just Altbooted the device, which would imply hardware failure, and since you can print to it, and view CWIS, it isn't a broken network card or bad cabling. And scan to USB doesn't use that anyway, which would imply the scan board(s) are bad. No idea where you will have to go to troubleshoot it, probably need a service manual for sure and figure out what parts are common between USB and Email and SMB, yet not common with Copy and print to narrow the field.
If you hadn't mentioned SMB failing with the same fault there is much more troubleshooting that could be done involving Time/Date/Subnet/Gateway/DNS and general compatibility in encryption and scan locations.