Typically no, if there's some payment requirement, then yes until the judgement is settled, but he's basically free to start InfoWars2 if'n he wants... And can find the money.
FedEx is so very complicated, FXG isn't union, Federal Express is, IIRC something to do with them being under FAA authority. Not sure about FedEx Freight, FedEx LTL or FedEx Expediting. And that's just part of the mess of the company. As to the name thing, that was started by RPS, FXG's predecessor, and was a single contractor buying a route from RPS, with RPS supplying vans and uniforms much the way Amazon does with their companies, but it's entirely possible that some of those drivers bought multiple routes and formed up their own little company, or that FXG followed in Amazon's footsteps and switched to contracting with companies rather than individuals.
I'm not surprised it won't be an electric Maverick, I don't think they're ready to make a new version, and the current chassis I don't think would work for a BEV, though I'm surprised they haven't made a PHEV version, as the chassis is shared with the Escape IIRC which has a PHEV version or at least had one.
If someone's willing to bankroll him, he could, but I don't think he's real popular right now.