RIGHT ON PH! I'm so happy you got all of your suit....makes me kind of sad that it comes at the time that I'm getting ready to sell mine ( dont worry, I got a custom Pred in the works)
I can try and answer some of your question, but some of the other guys might have better ones than me.
1. My backpack came foam filled, but I've had to mix a two part semi-rigid foam for other things...I cant remember the name of what I used, but Scott posted a link to a good foam in the materials thread here is the
LINK
2. Not sure why you want to glue velcro to the latex...not a big fan of glueing anything to the latex myself. PM me on what you are planning to do, and I'll see if I can help
3. The thigh armor can be tied on with leather strings...that way you can remove them at will ( I kinda liked them off) remember to tie the lower part loosely around the thigh to allow for better movement. as for the knee armor, a nice thick sewing needle and some grey upulstry thread. just stitch them on with a couple of tight loops.
4 Dap or good old hot glue always worked for me
5. This is a tricky one...resin or foam canon? hot glue worked for the lighter foam canon, but when I upgraded to the resin, I had to build a pad out of foamies to fit under the backpack at the shoulder..then I used a screw to sort of bolt the base on. For this one, I'm sure someone will have a better answer.
Most importantly, Enjoy your new suit man,.....you've waited long enough.
ps. If you arent going to mount it to an undersuit...use a piece of black elastic to attach each arm...one end of the elastic attached insde the arm and the other attached just under the shoulder of the torso. It gives a nice range of motion, and they wont rotate on you.