I decided to re-install toilet (new wax ring). I also re-assembled P-trap where the sink was and filled with water to prohibit gas from entering room. (sink and faucets still not connected as new vanity hasn't arrived).
However, I am still noticing the odor in the bathroom. I haven't done any other plumbing/drain work in the room. With toilet installed and P-trap assembly installed (and water in bottom of trap), I would think this would eliminate the problem. It hasn't. I am at a loss to what may still be causing the problem. I have even disassembled and re-assembled the toilet again.
I doubt it is a problem behind wall as there was never a problem before, and I didn't touch any drain/plumbing beyond the toilet and where the p-trap ass'y meets the drain coming out of the wall.