I'm presuming the motor worked OK before you pulled it apart.
You previously mentioned using 6 x 5S lipo packs, but mine would not work on 15S lipos because the voltage was too high for my controller. As long as the voltage was below 60V it worked fine, whereas above 60V nothing at all happened apart from the battery gauge lights.
I hope you refitted the plastic insulation material between the FETs and the aluminium heatsink plate, and didn't just use thermal paste, otherwise the FETs would probably have shorted each other out where they touched against the metal:
Is it possible that the wiring harness coming from the Pie could have been damaged by excessive movement while working on the hub assembly?
Are you 100% sure that all the wires were soldered back onto the correct connections when the controller was refitted?
If no obvious mistakes have been made, you will need to remove the cover and check the continuity of the wires between the controller and the harness connectors.
It would also be a good idea to check the voltages on the throttle connector too.
Unplugging the brake connector would also eliminate the possibility of a brake switch or wiring problem causing loss of power.
I've run out of suggestions for the moment, so let's hope you can spot something obvious with either the connections or the wiring.
Alan