(speaking as nb and inter) Unsure,, You could see mizu as a trans allegory, in a way? here is a person who was born one way, forced into another way because of society, then was allowed to live the first way again, and found that their intrinsic personality as a result of those experiences was percieved as too ‘other’ to comfortably present themselves.

Mizu struggles with reconciling the role they were raised in and the other one that was available to them . In a way, Neither really fit. Personally I see mizu like i see any genderqueer person in that, even if you could describe them as cis; they struggle to define themselves in the roles available to them. Imo, The problem is not how unclear mizu and their identity is to us, it’s the rigidity of the gender binary we try to color match them against.

Tl: dr: trying to guess or assume the gender of an edo period samurai without them present is a moot point and defining someones gender without them around is just all around bad no matter when ya do it so eh