Pretty much all Alolan Pokemon (including Alolan forms like Muk etc) are incompatible with certain TMs of moves they should be able to learn.

I.e. Alolan Muk can't learn Fire Punch through TM, even tho it can learn the Move.
Same with regular Alola Region Pokemon. Gumshoos for example also can't learn Fire Punch through TM even tho it learns the Move.

There are many, many others obviously but I just wanted to give a few examples, I guess.

With the examples you mentioned, those pokemon do not learn those moves via TM in Ultra Sun or Ultra Moon, which are the games we use currently for movesets (except for Meltan and Melmetal because they're not in that game). They learn it by Move Tutor and I imagine that's the case for all the moves and pokemon you're referencing,