In the end, it didn’t really matter for Fumero that there aren’t significant numbers of Latinas in the province (not to mention the even lower number who might be actresses who are also funny), because to her, any black, indigenous or person of color could have taken on those roles, instead of the producers automatically going for white actors in those parts.
Looking at her tweet thread, you’ll see that Fumero took about a day to actually look into the Latin population of Quebec and then return to share the rest of her feelings on seeing Amy and Rosa as white characters.