V.O. and Acoustic Instrument - First Timer

Greetings all! I am new to the forum, although I'm pretty sure I've seen some of the posts over the last few years as a result of searches. I would really appreciate any light the group might shed. Around two years ago, I purchased a house with a full basement and scored a nice *extra* basement room, plus a fairly large storm shelter. My intention had been to jump in quickly back then, but I'm glad it didn't work out. After reading this forum for several days, I think I'm just now playing about the edges of the vast chasm called "what I don't know". I attached a simple floor plan--the ceilings are 9' sheet rock (gypsum board), except for a 1' x 1'x sheet-rocked chase which runs along the upper corner of the long wall above the door. Carpet over concrete floor. You'll also notice the notch were I had planned stand up a quick stud wall for isolation and a maybe a bookshelf/cabinet. There's a bathroom directly behind it, so the water noises communicate through pretty easily. On the other side, I've already setup a double wall to isolate from the furnace room (the results favorably surprised me). In any case, this is the hand I've been dealt. :) Two things are motivating me: I've just taken a job that will be telecommuting a significant portion of time and I want to be able to track and mix small projects to the best level of quality possible. Podcasts, voice-over, vocals, ensemble, and acoustic instruments. Well, that and the fact that I love to do things myself. Last year, I thought I knew what I needed. Four to six inch 703 or rock wool traps all along the back wall, in the corners, and first reflections. Then I started reading around this site. Sigh. I'm interested in the most even response I can get in such a small and poorly-shaped room. So, three questions*: First: looks like I should be essentially following the plan (linked above) for corner slot absorbers, side panels, and front/rear wall absorbers? Any alterations that would work better? Cloud over mix position? Second: What should I do about that weird (what I'm calling the "rear") wall. I planned on putting a bookshelf in and just hanging a corner trap over the top of it. And more to the point, am I orienting the room correctly to most minimize problems with that asymmetry? Last: Will there ever be any value in trying to convert that shelter into a vocal booth at some future date? It would probably have to go pretty dead--it's all concrete know and sounds exactly like you'd imagine. No real plans, just curious on this one. Thanks again! --Joe *That is, I have these three questions unless I'm totally off-base. An unfortunately very real possibility! :)