1. If memory serves, the NES controller is smaller in width than the NES dust cover, and the cover may get in the way when playing.
2. Is the Family converter going to be in any way attached to the dust cover? If so, you may not want to, seeing as the flimsy dust cover cart slot probably couldn't take the constant re-insertion of a zero-force insertion cart slot.
3. The PSOne screen is much bigger than you have depicted; the motherboard is large and rounded, not square. So you either have to make the case larger all the way around, or just make the part that houses the PSOne screen round.

