The matter of who would be chosen to accompany them to the Auction was eventually made by Countess Dewinter. There were a few Families that she wished to do business with, who weren't trying to marry her off to their sons, and who had seemed friendly at the party after they had seen all the improvements to her estates, instead of turning greedy.
The way that they had responded to her sudden good fortune said a lot about their character, and those were the ones that she recommended Wolfe to get closer to.
It was a given that they would try to make a deal with him for the same sort of arrangement that the Countess had made, and they would likely be willing to buy whatever Wolfe wanted from the auction to secure it, so he wouldn't be dumping a load of fraudulent coins into the market and messing up the local economy.