I can only help on your scenario #1, 4.6L auto 4x4 Supercab, but with 1997 info, should be same for 1998.

With 3.55 axle GCWR is 11,500, max trailer is 6,600, GVWR is 6000.

With 3.08 axle (I would avoid 3.08!) GCWR is 10,000, max trailer is 5,100, GVWR is 6000.

Payload on the S/C 4x4 is only 1,365 minus people and opt. equipment. Choosing 4x4 drops towing by 400, and payload by 400 vs. the 4x2 ratings.

If you back off of 4x4 down to 4x2 to get the power, mileage, towing and payload back, you probably want the Limited Slip rear axle for slippery boat ramps.

I don't know of any site that lists the information you want. If people with newer trucks have a brochure, they could look it up.

Good luck with your hunt!