Those connections are scary small! The speaker connections in particular are very fragile and hard to get under to lift off. One of mine came apart, but it could be reassembled by first placing the plastic connector in the socket and carefully connecting the metal terminations into it. Be careful to orient the slot in the wire termination so it is vertical to interface with the lug in the socket, if that happens to you.
I had the dreaded "3 beep" (memory failure) problem and ordered a new logic board. Only when I had the old board out did I realize there was a compatibility problem- different board versions, connectors did not match. Since I was stuck anyway, I baked my old board in the oven (325 for 10 minutes) and reassembled it all so I would not lose any parts. I was surprised to have it boot up with the old (baked) board!