I assume you can redo the photography? If I was doing it...
Lower the camera and make the lens axis perpendicular to the product (so you are not looking down on them.
Fix that zip. Tidy it up even if you have to reinforce it internally to make it flat.
I would definitely consider marking the position of the case and relative position of the products, and photograph them outside the case. I might even do that individually. Photograph the case while empty, and composite everything back into position. That way there'd be no need to use polarizing filters to eliminate reflections on the face of the case.
I have a BIG octobox that I would use for lighting. There are no tricky surfaces to cause problems.
There'd be a decent skill level to do all that convincingly, but it would be doable.
Having said all that, if I was in your position and wanted to ask for advice, I'd be look for a stylist to ask rather than Photoshop users. Stylists can be a product photgrapher's secret weapon!