I was one of the largest volume purchasers of original Topps proofs at the 1989 guernseys auction. To help answer the question: 1) for the regular issue cards there are all color combinations available for most. The proof sets I have range from 7 to 11 different examples of any individual card. These are the possible combinations.
1. Yellow
2. Magenta
3. Cyan
4. Black
5. Full color no Black
6. Full Color
7. Yellow/Magenta
8. Yellow/Cyan
9. Magenta/Black
10. Magenta/Cyan
11. Magenta/Cyan/Black
If you want to see examples go to this link on Ebay in my store:
https://www.ebay.com/itm/204402402724
I have hundreds of proofs in the store as well. Jeff W