[Bokonon]

This outlet it turns out is the only GFCI in the Gargae. Is it safe to try and use the non-GFCI outlets in the Garage for charging? From what I have read the UMC-2 has a built in GFCI so I want to make sure it is not dangerous to plug it into these other outlets.

You should be fine.

The UMC has ground fault protection built into it, which covers the length from the UMC to the car. From the wall to the UMC (i.e. the pigtail) there won't be protection, but unless the area around the outlet is wet and/or you plan on unplugging the UMC from the wall while the car is charging (please don't! ) it shouldn't make a difference.

Separately, if the circuit you'll be using is connected to a 15A breaker, and there may be other loads on that circuit while charging, the breaker may trip if the car is set to charge at 12A. In that case, set the car to charge at 8A instead.

 

[Bokonon]

Can I keep it at 10amps or reduce it even lower on the new outlet (non-GFCI) to 8amps as you mentioned? I believe the Garage has its own dedicated breaker according to the fuse box, but I haven't tested this to verify (flipping breaker etc.)

Sure, there's no harm dialing it down to 10A or 8A if you're unsure of what else is running on the circuit and the slower charge rate (probably 2-3 mph in winter) gives you enough juice.

There also isn't much harm in trying out 12A to see if it trips the breaker (assuming you'd have enough range for tomorrow if it did trip). It sounds like your earlier interruptions were due to ground fault detected at the outlet, rather than an overloaded circuit, so you may be fine with 12A. If not, oh well, the breaker trips, and you can dial the current down to 10A or 8A.