Dang, you're a star on this stuff. As I was reading the initial post, I was already keeping notes in my head of the corrections this needed, and you knocked them all out, except for maybe one other I would mention:
1. Make sure the electrician doesn't use a Leviton outlet. They are horribly cheap and crappy and way too easy to have bad, loose connections. Any of these other brands are all pretty good: Cooper, Bryant, Hubbel.
2. It says 50A breaker, but 8 gauge Romex is only good for up to a 40A circuit, so that's not OK.
3. Yes, the naming 8/3 is already defined as 3 conductors, plus the ground wire.
4. And even if it was switched to 6/3, that can't be swapped up to a 60A circuit later, as
@golferguy was suggesting.
5. An outlet installation for EV does require using an annoyingly expensive GFCI breaker.
I don't know why so many people assume that ALL panels can ALWAYS use tandem breakers. I have a fairly decently modern Square D Homeline panel from 1996, but it does not allow any tandem or quad breakers. So a subpanel may be necessary and isn't that bad of a deal.
If it's using Romex, it's probably because it's in a location that needs to use Romex. The place the line is running usually determines if you use wire in conduit, or cable. Above ceilings or inside walls is generally not going to be conduit.