If you're willing to try out games that aren't on your list, there's a couple other games I'd consider checking out if you're looking for a good beginner-friendly game. Firstly there's Fantasy Strike, which is deliberately WAY more simplistic than almost any other fighter you'll find. There's no special move inputs at all (Quarter circles, ect) and combos don't extend beyond 2-3 hits generally. The actual execution of the game is very low, so you can focus on the gameplay very quickly. Of course, the downside of this is that the game is so basic compared to other Fighters that while it will teach you some fundamentals in terms of the genre it will be very hard to transition from Fantasy Strike to other more advanced fighters because you still won't know how to do things special move inputs or integrating combos into actual matches. Also a lot of people find the art style and animations very bland so it's not the most exciting game to look at.
The other big one not on the list is Them's Fightin' Herds. This game is PC exclusive currently with console ports likely being extremely far out in the future, but in terms of accessibility I think it's very good on that front while at the same time still being very comparable in terms of depth to most of the other big fighters out there. You mentioned that you wanted a game with a good tutorial, TFH has the best tutorial on the market period. It's incredibly good at teaching you core fighting game concepts in a fun and interesting way while also having lots of personality. The combo system in the game is very deep but it's also extremely flexible, so you can come up with combos that you can actually perform rather than other games where your routes are more limited. The game has special move inputs but they're generally the most basic ones such as quarter circle and down down motions. Also due to the game's aesthetic and origins a ton of the people who play it haven't played any other traditional fighters before so there's a lot of newer players that you can play against. The main con IMO is the artstyle, while it's all animated fantastically and is overall very good at capturing the aesthetic they're going for I can completely understand why people would be massively turned off by it.
As for the games you listed I think the clear pick is Killer Instinct. KI is an absolutely fantastic fighting game, and thanks to its combo system (and its breakers) the game is actually super easy to pick up and be able to do cool stuff with while also having a crazy amount of depth and a good path of skill progression. It's an absolutely amazing game and it's one I think everyone should check out.
For the other games listed, SC6 and Tekken 7 both have absolutely trash online and unless you have people you can play them locally with I don't think it's worth the hassle. MVCI is "dead" at this point, very few people are still playing it. MKX is probably the 2nd pick IMO on that list, but it's also an unsupported game as the team is supporting MK11 right now.
