you have gnx #97 , I would definitely use the OEM GM fillers you have in plastic, are they already painted??
as for the hood shocks most mainstream sellers like kirbans, gbodyparts, highway stars, classic industries, Original parts group one of those should have them, you can look at headliners there too or go onto parts wanted section and do a post.
a reputable body shop or auto re upholstery shop can fix headliner , do your research on those shops