Which is funny because that translates to "fully garnished" not "all dressed". Tabarnac

IMO that's a mistranslation; “stuffed with everything” would be more accurate.

Here in Ontario English we call that pizza deluxe!

Depends where in Ontario!

I'm in Ontario but in a heavily French area (i.e., East of Ottawa) and "toute garni / all dressed" is common. You'll find it places like Ottawa as well given the proximity to Quebec and French population.

That is what OP said. "All dressed" is a direct translation from French.

Yes, they both refer to the same pizza. Many francophones actually say "une pizza all dress" - it refers to that specific combination of toppings though, not literally every available topping.

Do you call “tomato sauce” “red sauce”?

I can't speak authoritatively for the OP, but yes, I would expect red sauce to be tomato-based. Compare with "sauce brune" [brown sauce ~= gravy] which is what gets put on poutine.