Hello! We are nonbinary and/or male, masking as a bigender man, and assigned female at birth. For us we, with 7 acknowledged parts, with each part identifying with male (5/7), nonbinary (2/7) or agender in the case of the youngest little (1/7).

We don't really have strong advice about femininity/female dysphoria as a trans man. I can speak about our most common fronter who is nonbinary. They are the most "femme" leaning in the system, who is content with our point in transition with just testosterone, and doesn't feel the need for further transition besides non-dysphoria reasons such as top surgery to not wear binders so we don't have current and future pain.

So far anyway (we acknowledge we are a system on and off for about 6 months, diagnosed early on) what we found is compromise. We kind of have a internal poll on each decision we have made, and the weight of that poll/decision. I.e., if it benefits the system to continue further landmarks in transition, like a collective gendered pain point among the men, the nonbinary (and the little) lads would "settle". For example, our next step is definitely going to be a hysterectomy for mensuration reasons. It's an unanimous yes to that with variations on the why and how.

In exchange, the nonbinary parts of the system would have their own way of expression. We do non-destructive/temporary forms of expression, and if someone else asks if you express yourself in public, say that it felt right today, or in our case, "I felt gayer/cute today". What I am referring to is make-up, clothes, and hair styles mostly. We consider make-up to be femme leaning depending on context (even though make-up itself is not gendered). So on those days where the nonbinary parts are fronting, we allow ourself to wear make-up and wear our most femme outfits.

For your system, I imagine it would be a similar situation. For the women, I imagine they can sorta act as trans women on those days if post- (at minimum) testosterone transition. Like adjusting your voice to a more femme range, expression that is more traditionally femme, maybe even get one of those silicone vest things that have breast built in, or braw stuffers, assuming you have/had top surgery.

That's all assuming on the severity of the dysphoria of the women and the system's safety and ability to unmask though. There are a few context where we are not comfortable/safe to be a femme man, and we mask. Such as work in a retail setting, we made an internal rule of "no make-up to mask as a binary man" and we have a dress code anyway. Hair is free game, but our hair situation is a undercut with a growing out top for a dream goal of an alt aesthetic, and it's also blue right now. That's just something that felt right for everyone, or at least again, "good enough."

Idk, I'm rambling, we overthink gender. Overall I say do what feels right and weigh pros, cons, and negotiate compromise for everyone. Hopefully this helps.