Awe...some...Na...tious,good work sir...been very busy I see. I the wifi on the Zero W isn't perfect out of a tin. Fair amount of Packet loss. Wouldn't want to rely on it too often at any distance from the router in any scenario.
I SSH'd into it via wifi and it seemed pretty responsive, actually! I should do some speed tests. The pi is mounted right under the buttons, so I suspect having it there with the lid open probably helps a lot. You'd only really use it to transfer the occasional rom or tweak a setting or something anyway though.
This is a really nice idea.
The only downturn: i think that the edges are too narrow, so that your palm-nerves will get irritated when playing for a too long time.