We would have to consult an array of opinions on this matter to really settle it, but I don’t think we can call all of them the Roman Rite. The monastic usages are, for the most part, only adaptations of the standard liturgy of their times which was generically Roman. But the Ambrosian rite most certainly has, despite Ambrose’s wish to conform in most things to Roman practice, its own independent history of development. Its structure is fundamentally different from the Roman rite, both within the liturgy itself and within its external disciplines (with a Lent of different length and practices, for instance). It’s been a while since I read up on the Mozarabic rite, but I’m pretty sure the same could be said at least of the elements of the missal itself (having more propers than the Roman rite and also placing some elements in different places during the Mass).
PS - I should say that my comments on the Ambrosian rite refer to its classical expression. Much was done when they “renewed” it in the 70s to conform to the ordinary form of the Roman rite, so much of that distinctiveness might have been lost, but I don’t know much about is modern form.