Shower

If you do put that on, point it upward so it will drain away rather than form a water pool that would freeze. Most quick disconnects have a spring loaded device to prevent flow once it is disconnected, and gravity will pull the water out if you align it properly.

Hose type fittings???
One source
Or hardware stores will have them. Probably cheaper plastic ones.

Take off your hose,take off the shower head go to any big box home store and tell the person in plumbing what you wanna do.'
Easy as pie.