Wayne's World exists in a universe where there's apparently self-mending jeans and dinosaurs, as seen in the second film. It's just a comedy where random stupid stuff happens, while Scream is a
fairly serious film series throwing aside the meta humour. The View Askew series is actually interesting because they're mostly comedies set in a realistic world, although it can get very silly and meta in some stories such as Jay and Silent Bob Strike Back. Kevin Smith actually endorsed Zack and Miri and True North as canon too, and they're not part of the View Askewniverse series.
Also, nothing in that scene tells us he's playing the same character except maybe the credits and even if he was, then Terminator is a time travel franchise where there's a ridiculous amount of offshoot realities. In other words, Wayne's World doesn't have to be part of any Terminator timeline in order for that to be the T-1000. That was also Robby Koch in the picture, so technically not John Connor.
I'd say it's a toss-up. I see it as more of a Detective Clarkin in Annabelle/Wolves at the Door or Father Parez in Annabelle/The Curse of La Llorona (TCoLL is technically not an instalment of The Conjuring even though it's canon), rather than the T-1000 in Wayne's World or Last Action Hero.
Schrödinger's canon.