My 2 cents:
Clean the rust like others have recommended, it'll come out fine, with a nice patina.
Those adjustment screws are not like any other. The plastic stop is threaded. As long as you can put the wheel in against both stops and the wheel is centered (look for equal spacing between the rim and chain stays) they you're good to go. If not, you'll have to clamp down on the quick release pretty good so it doesn't slip.
__________________
If someone tells you that you have enough bicycles and you don't need any more, stop talking to them. You don't need that kind of negativity in your life.