Well, starting from seed, a month to veg, two months to flower -- no matter what you do, it's gonna take about three months to get to harvest time.

24/0 works great, forget whatever you heard that it doesn't. Sure, 20/4, or 18/6 works too, but less light/day = slower growth = less bud in the end, sooo...

As for the noise being too loud for a bedroom, that depends more on you than anything else. In my bedroom I have four small fans going, plus a 6" centrifugal fan. The 6" fan is sorta loud, but it's also a drone, and it didn't take my brain long to just filter it out. It's just white noise to me now, hardly notice it at all. If your concern is that OTHER people will notice the noise of a centrifugal fan, yes, they very likely would. I turn mine off when I have to let anyone in.

6' height is great. ScroG is great. 24/0 for veg is great. Forget CO2. You're on the right track.