I checked the oil cap and didn't see any of the "white residue" mentioned.
So just to make sure I'm on the same page with everyone, I will need the following to complete the job:
Victor Reinz/Intake Manifold Gasket (MIS16203A) | AutoZone.com
Delphi/Intake Manifold (FH10095) | 1998 Pontiac Grand Prix 6 Cylinders K 3.8L SFI OHV | AutoZone.com
Anything missing/wrong with these? Also, I'm gonna go ahead and replace the coolant elbow (again) just to be safe.