Assuming the caddy is SATA it should work no problem.

There is a slight chance it might reduce CPU\GPU clockspeed during usage, so as to not overload the charger.

RAM speed has no relations with CPU speed. It’s fine.

Typically that’s caused by plugging in the charger as a whole, which draws quite a bit of power and as a result will arc.

A socket with a switch wouldn’t have the issue when the switch is off, the wear would then be on the switch.

Yes.