Hello Andy

One by one:

T312 - battery voltage too low
T860-863 - traction Power Module leftside error
L225 - pump motor doesn't reach the proper speed, although the signal from the controller is present
L286 - too low current on lift joystick
T421-425 - the communication between Can bus and power module rightside is faulty.
T900-963 - power module rightside error
L800-863 - lift power module error
T411-415 - the communication between Can bus and power module leftside is faulty.

Uff - looks like total disaster.

But probably the problem lies in:
1. Power supply. Check battery, high voltage cables, fuses, main switch, cable connections.
2. Electric motors. These are 3-phase AC motors and any short circuit can give very strange output
3. Least possible but possible. Earth connection.
It may happen that the truck gets "loaded" and needs to be connected to the earth.

Good luck