Good luck with that. Even with my experience with fiberglass I wouldn't want to be in your shoes! The one thing that I would recommend is to reinforce it as much as you can, and I would try to do as much of that from the back side or you'll end up with a lot of finishing work. I would also add some dampening to the pieces since it may become buzzy at certain RPM's and speeds due to the light mass of the mat and resin alone.
Integrating such a huge piece without it standing out will be the tough part; seams, color, panel transitions, curves, etc. I know you are already going, but you could have put wood pieces in places before you glassed over them if you wanted to add strength or where you need mounting options. With the center console being low and omitting the armrest I think OEM carpet color would look good.
CarPC is nice for upgrading each component, but tablets are nearly lag free for any kind of media. If you want resource hogging games then CarPC is the only way. But some new tablets have the Intel i5 Haswell chip so they are fast and run cool.
so will this piece be removable? i see where youre going but im wondering if you can pull this out so you can get to the cabin air filters under passenger dash(would help to change them if there's any smell from building materials later on) and get to the carpet if you wanna change it or re-dye it.