The "nice" guy who interacts with children and parents, and submits to the authority of a female principal. Does he have the respect of moms and female teachers? It's unlikely that he would be sexually attractive to them -- even those male teachers who are more manly are constrained by the environment and the nature of the relationships he has with others. Does it imply that there is no respect? After all, he's just a teacher, no higher in status than a woman occupying the same role (and possibly lower), and most likely of a lower status than a principal. What respect does he get as a male member of the polis? That's irrelevant. Who would look to him as a leader, except for the children? Even if he exercises leadership over the other teachers, would that elevate his status among the women teachers?
It seems that respect is not the same as sexual attraction but these days, sexual attraction is a motivating reason for women to give respect. Or at least recognition of a man's charisma. Is it possible for a woman to do so without feeling a little bit of attraction? Is respect (or submission) more emotional than rational for women?
Alternatively, is genuine respect compatible with being "friendzoned" or put in the categories of invisible or nice men?
I would guess women teachers would not consider marrying male teachers because of hypergamy, unless they happened to be short on options.
It would be emasculating to be the subordinate to a female principal, unless somehow he could game her and therefore have some sort of directing influence on the relationship.
And there's always the possibility of suspicion that there is something off -- he's "too" friendly towards children or relates to them too well. Child abuse. Forget any sort of gift-giving and the like.
What about the "good" dad who copies mom instead of being dad? Does he create any attraction to him in his wife by doing the tasks of a mother, or carrying a child in a carrier? Would these even be good "beta" LTR traits? Again, this might be a question not of logic but of emotion.