A small pi

So I bought a pi zero, and I want to put Retropie on it, easy enough, I have the card baked right now, but I need to update the emulators on it (and on my 3b) I figured out how to update the cores, man it was a pain, but I cannot get them to show up in emulationstation I have to go into retro arch to access them, anyone know how to do that? All the guides and instructions I have found so far seem to assume I already know how to do everything to it.
And I may be crazy but they should have designed the pi with a safe shutdown mode.
And does anyone know if I need a powered usb hub to use an external WiFi adaptor and keyboard and mouse with a zero (I know I should have for a zw, but this one was cheaper atm) or would I be better off sharing my internet from my Mac and just ssh into the pi to sleep the cores. Though can’t I just do the cores onto my Mac and put them in the card for the zero?

I know it’s a lot of questions about a different product but I trust ya’ll