I’m going to insert some of my own opinions on this post: I don’t think that seeing Mickey as a male and Minnie as a female because of their clothes/names/voices necessarily means that you think that gender is a social construct. I do, however, think it means that gender roles are artificial to an extent. What might be considered to be “masculine” attire by one society could be considered to be “feminine” by the next. Same goes for names (they don’t objectively have a gender).
I do think men and women generally tend to sound different and that is rooted in biology, so I would assume that a character is a specific gender because they sound like that gender. However, there are cases where someone can sound like the opposite sex and dress/look like the other gender (ex. Many traps in anime). When that happens, I’ll label that character’s gender as whatever they’re biologically stated to be, regardless of how feminine or masculine they sound/look.
Gender roles socially constructed, but gender itself is a biological reality. If a woman is named Nathan and dresses up as a guy, then her gender is still clearly female despite having masculine attributes.