Maybe treat it like two closets. Like seperate it into a flower room and a growth room. Maybe rack or layered system in the growth room like split the verticle space 60 / 40. Could have mom down below and kids above. Saw something like it somewhere online.
I am sure you have read all the post about reflective material or paint. I made sure my vents were at the top of the room and that worked out. I had air inlets below but that is a problem. I should have more fresh air coming in and now I have to find a way to cut another hole to outside. Dealing with exhaust cooled Sodium required another in and out for the air. So that was my mine mistake. I have eight footwalls and use yo yos to hang from center and that has worked out.
I am sure you have thought about wiring and where you want your stuff. I wish I had put mine just inside the door. Anyway it sounds like you have a prime piece of real estate and the experts here will chime in and help you out.