Have you tried contacting a local car windshield replacement company? I’ll be curious but I know there are non Volvo “generic” replacement windshields. I wouldn’t be surprised if they were not that far over the average car. I know that was the case a number of years ago. The demand is certainly low and I could see them being eager to move out extras. Let me know what you find.
The backglass seal would be a Volvo part but check with the dealer. Are you talking about the trim around the window some other part of the glass mounting?