(cue the choir)
That’s about as awesome as it gets. You won’t know what you don’t know until you know, you know? Once you get some plants going in there, you’ll be able to figure out the fine tuning, timing, etc. Homework is good! Do lots of research, ask lots of questions, and don’t worry! You’re in very good hands here. Lots of pros already on this thread. Welcome to ILGM, @letitgrow!
Here’s my spitball: I’d figure out a way to section off the room into two sections, either another couple, larger tents, or a temporary wall covered in panda film. That way, you can have a separate flowering section that you’re constantly rotating plants into. That would take a lot more lighting, if you plan on using the entire room. For now, though, I’d put one light in the tent, one outside it. Then you can have them on two different schedules. I’d put the younger plants in the tent, since they’ll take less space. Then when you add the third light (if you want to go with all HID) you could make your flowering space larger. The only issue there would be timing. You wouldn’t be able to go in other than during “daytime” for your flowering plants. Unless you run all autos. Then you can just light the hell out of the entire room and go for broke filling it haha!
I know the guys with more experience in this stuff will give you great advice on the specifics. I’m just the pothead welcoming committee. 
