Oil fill cap. If you cannot find the oil fill cap, you have no business doing your own repairs. Do not overfill or you may damage your engine.
No.
Yes, it will fit.
Yes.
5 Quarts
10w30
10w30
10w30
5w30 or 10w30
5 quarts
5 quarts 10w30
5.5 quart
You need to put a little more detail in. What engine do you have, and what engine did the 99 have?