Propbably not a good idea to advertise it as having PS1 and DC emulators, the guy might buy one and then realise it doesn't actually emulate them adequately or worse still none of the games actually run.
To the OP if you want to emulate up to those levels you'll need a decent Android console, I have a GPD G5A and it's only $108, it emulates all those systems you mentioned and more.
GPD Win, GPD XD 64gb, Pap KIII-Plus, RS-97, RS-90, New Bittboy, 3DS XL, DSi XL, GBA SP, GBBC Clone, Gameboy Pocket, PSP Go,
HP Envy M6, Acer 522, Dell Mini 9
Psion 5 & 5MX
Tons of other old laptops and tablets.....