The first 81 may be the best buy because it is not able to be inspected before the auction but both 81's are actually worth about $1200 to $1500
The 72's are a little rough so I would not bid more than $300 to $500. The primered one is in best shape but has the small letters and is less desireable.
I can't see the Dr. Pepper selling above $500, but in Texas Dr. Pepper is king so ...
One thing to keep in mind is that a Cavalier 72 is much easier and cheaper to restore than an 81 when factoring in chrome plating, coin mechanism rebuilding, door liner replacement, powdercoating bottle stack faceplate, bottle door medallion etc. although the 81 sells faster and for a higher price than a 72.
Anyways, it should be a fun auction........keep us posted