As long as the 1999 has the 3.5L engine, yes.
It will fit either way. Whichever is easier.
No, it will not fit.
yes
Yes, it should.
I have factory 96 Cutlass 5 spoke Aluminum 16" on my 01 Alero
yes
Yes.
Yes, It's the samething.
yes hoods are the same 2000-2004 ls1
If they both have a similar engine, yes
No, they are different generations and therefore require different hoods. A 98 hood would only fit on a civic from 1996-2000