These are more pictures of the same case you posted earlier, right?
I could never get away with fabricating a computer on the kitchen table.
Oof, there goes the grounding... will be a nice campfire, though.
A ground strap could be used to tie the components to a common ground.
I wouldn't worry too much about grounding. Your components have a ground path through the PSU. Just have to remember that any screws on backside could become energized through a ground fault. So as long as your not grabbing those screws at the same time ground fault occurs, your good. Wood is a great "Insulator" of electricity.