1. I doubt that these guys have a snowball's chance of killing a squatch on camera. It just isn't that easy to do. Only once in my years of doing this have I been party to a situation where it would have been possible. In 2013, we were camping at a hot spot/habituation spot that we frequent. We had a lot of activity. SRA-Todd went out of camp quietly with a thermal and ended up watching a large (9 foot) squatch for nearly 20 minutes as it came to our camp and watched as I played my flute. Had he had a gun and thermal sights instead of a viewer, he could have easily shot it in the head. That said, given the demands of film, getting one in your sights while filing will be damn near impossible.
2. My fear here is copy cats, especially young drunk copy-cats targeting human shaped prey.
3. Reprisal from the squatches is a very real threat, but then if you are stupid enough to shoot one, you deserve whatever they dish out to you. Remember Jayjeti's rock throwing story. They will get revenge and then some.
4. I do believe that they bury their dead, either in bogs in the Midwest or in cairns out west.