One mm wobble isn't too bad, two is getting there. I'd want to true them better than that though. Trueing and even buiildinv a wheel isn't so hard. You need a spoke wrench and patience! If a nipple is stuck though it's harder.

About derailleurs, first, they have a pair of screws to limit how far they will move. You should have no trouble identifying them. Make sure they can shift as far as necessary but no farther. Oil them so they move and refurn easily. There is no great magic to it. If the csblex dkn't move eadily, replace them snd any housing. Good tools are essential, especially cutting cables and housing.