Ha! I tried exactly the same thing last weekend. The only things I could feel a bit loose were the blue connector blocks to the left of your red ring in your last photo. I put a bit of silicone between the connector and its mount, it's secure now, but made no difference to th knocking.
My gear cables already have rubber tubing around them towards the bulkhead, but I didn't try changing gear to see if they moved and rubbed, shall have another look.
I also didn't seem to find the airbag from just taking the glovebox out, is it blatantly obvious or do you have to do it by feel?
I think I'll also take the centre console out at some point. It'd be great to get to the bottom of the noise.
GT 3.2 V6 - Q2, KONI FSD & EIBACH PROKIT, GTA REMAP, MICHELLIN PS3's, BMC CDA
159 SW 2.4JTDM TI - ALFATUNED, WIZARD BACK BOXES, KW V3 COILOVERS, NOKIAN WR A3/MICHELLIN PS3, PCA DYNAMICS ALIGNMENT.