Android is a bad idea!
Making many versions of the console is the worst idea, this is the best way to fragment the community, you should only make one version in differents color but not a touchscreen version and another one with no touch screen you sould put a resistive touchscreen with a stylus since i don't think that people would use it with finger and a resistive would be great for Scummvm, mini USB is dead today use micro usb instead and 640*480 would be better for PSX and N64. And no need an OLED screen if it's a good LCD, not like the Dingoo(very bad) and Caanoo one(screen bleeding)