Hey Rain, your mixing / producing space has dimensions very similar to mine, even down to the placement of the door! It's the latter point that got my attention - regarding your question about bass traps, or the lack thereof. I figured out that in my smallish space, whatever corners could be covered by traps should be. So I got thick mondo traps (I got 4" thick but you can get them 6") and mounted them in the three corners that I had minus the door. Even with three-out-of-four, it made all the difference that you would expect from adding traps - tightened bass and focused imaging.
I mounted them with a single hook screwed right into the corner of the walls where they meet. The traps had a cord on the back so you could hang them right on the hook, just like a picture frame, except kitty-corner style.
Since you're in a rental space, I'm thinking that the fix-up would be pretty easy. Just fill the hole with joint compound (or filler and then joint compound), sand, prime, and paint. If you don't have a can of your existing paint for touch-ups, your landlord will love you for asking for one!
Happy listening - and by the way, congratulations! (I must have missed the wedding - I haven't been lurking on these forums for a while.)