Use PVC for the drain line. It does not require insulation.
3.5"
A pipe cutter is the best tool to cut PVC pipe.
this depends on the class of the pipe as the higher the class the thicker the pipe
Yes, if it is rigid PVC conduit approved for electrical installations. Don't use PVC water pipe as it will be rejected if inspected.
Yes.
It will connect to the PVC pipe into the wall which ultimately will connect into the main sewer line outside.
No, do not use glue. Use teflon tape or pipe dope on the threads. You should also make sure you always put the male PVC thread into the female metal thread. If you do it the other way you will tend to split the PVC fitting when you tighten the threads.
if your waste pipe is PVC and your glue is for PVC . yes! but make sure to use a primer(cleaner) on the pipe first.
Absolutely Not!
Use teflon tape with a little pipe dope. If you don't ever have to take apart again then you can use glue which you are calling cement
Maximum PSI rating is on the outside rating of the pipe