Regarding sealing in the windscreen, I had to replace mine from an encounter with a rock. Had a local glass repair shop provide the windscreen (light tint green and tempered as original) and fit it in the frame, $400. They came out, helped me remove it, took it to their shop, installed the new glass and returned to help me install it. So maybe see what the glass shops recommend.
Noted that the holes in the side panel pics look very large. How were the panels attached to the frame? Are the holes in the frame that large?
And finally, when deciding on what material to use for the dash and side panels, be sure to consider what you are going to do with the seats so as to not get a mismatch.