Looks good. Make sure before you get your drywall on the unfinished side that you take time to caulk all the gaps. Then, once the drywall is up, caulk some more around the drywall joints around the door. Every little bit of sealing helps. In my control room, my ONLY sound leakage is from the door (as far as I can tell), so it is worthwhile to suggest you pay special attention to that detail for getting it sealed.
As far as your question about recording goes, if you use the inserts as I mentioned earlier (ie. first click only) your signal will not get interrupted as it flows through the mixer from your input sources, so you can mix the inputs however you want during the tracking. You'll probably have to re-connect things for mixdown, unless you intend to only have 16 input channels connected and the other 16 channels on your mixer will be hooked up to the recorder outputs (if this is your intent you must be sure that you mute the recorder outputs during tracking).
Myself, I have 2 mixers plus an outboard preamp that I use while tracking. I have a Tascam 16 channel mixer that has direct outptus on the first 8 channels (I think the preamps sound better than my Mackie's), so I usually use that for tracking the initial band tracks simultaneously (drums, though, can be an issue; most of what I've done to date have been with electronic drums at least for initial tracks). I then use my 2-channel preamp for tracking everything else direct to the recorder (except drums, which is another beast). I run the outputs of my Mackie MDR hard disc recorder into my Mackie 32x8 mixer and run the headphone feeds and rough mixes through that. Once tracking is completed, I have 2 options I can go for mixdown: either mix through the 32x8 with the minimal outboard gear I have, or pull my hard drive carrier from the Mackie and pop it into my PC to mix with Cubase.
Anyway, keep us posted on your progress. Watching what everyone is doing has been a lot of fun for me.
Darryl.....