If you’re gluing PVC to PVC then yes, PVC glue is the best option. Otherwise it depends on the application.
Yes, the heat gun was used to bend the top over on the gun body.
I had to dig through my old progress threads at the ASAP and Proptopia forums for my first pack build, but I couldn’t find a picture of how I mounted the ALICE frame to my motherboard. I’ll be sure to get one for you tonight.
My first pack (Mark I) was scratch built and I attached most of the components directly to the motherboard like you’re thinking about doing. I used some bolts and large ■■■■■■ washers for this from the inside out. I.E. - they went through the motherboard into the ALICE frame. I fastened them together with wingnuts on the ALICE side for easy detachment.
While they don’t have what I’m talking about in regards to the bolts, here are the links to my old build threads. What you’re planning sounds close to what I did, so they might be of use to you:
Update: I just realized you can’t get to those sites unless you’re registered. It might be worth it to do so, if for no other reason than to see build threads from folks back in the day.