[Gallagher]

The other parent will be a half-blood witch/wizard, haven't decided which it is yet. Mixing the uncommon squib with anything more impressive is going a touch too far for my tastes. Not trying to make a mary sue.

Thinking reasonably, secondary roles like headmistress, caretakers, nurse, etc. would only be called upon in certain circumstances, and otherwise be very minor. Even the teachers wouldn't be constant, though more so than secondary roles. The focus first and foremost should be on the students, and other characters don't need to be constantly posting, so long as they can be where they need to when called upon.

The headmistress, I'd imagine, would spend the majority of their time in the office. Most responsibilities, while needing time and attention, could have those involved meet there, or be taken through letters and the like.

Headmistress and a teacher should, in an ideal world, have fairly minimal posting requirements. Even combined, it needs more keeping track of others than your own posting.