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.

You can. Capacity doesn’t have a limit, the Up to stuff is just what the manufacturer can offer you.

You could look up your CPU name and have a look for socket. If it contains BGA then forget about upgrading the CPU.

And most likely your system has one of those CPUs, so forget about CPU upgrades.

It’s best if you list the model number of said laptop.