Since "defective power" is a red flag, I would go with the best solution possible.
If you are using HDSDI displays, they likely have greater tolerance to off voltages than the camera brain. No reason everything needs to be powered from the same source.
Meons have been out there for a while. The new version I learned of was found at this link:
Cannot vouch for it as a solution to your specific needs, but it does seem to have enough outputs for motors and displays.
Let us know what you find out.