[walrus01]

It sounds like each "MEP" (mission extension pod) once attached is its own fully autonomous satellite? How big is each MEP? Like, a mini fridge?

Since the mission is designed to attach one and then leave to go to another satellite that needs servicing?

[GlenTheMachine]

Sort of mini-fridge sized. They take over attitude control and propulsion for satellites that are low on fuel.

"Since the mission is designed to attach one and then leave to go to another satellite that needs servicing?"

Yes.