You can still get them if you have a haunted head, so I think the auction is fine as it is or maybe 54 minimum for them, like heads.
I do not believe that the issue of the minimum quantity of haunted candy required for a valid auction was ever solved. I been keeping an eye out for this, ever since this came out, and the last thing I remember, was that it would be decided some day... Would it be 54 of one type candy? 54 mixed? DC full of one type? No idea until the powers that be give us the requirements for what constitutes a valid auction for haunted candy. As of right now, you can still sell in the business section, and player shop chests.
Id asy if you have 64 in each slot (they do stack) of mixed (they have the same effect) typed, you are good. If not I wouldnt unless staff say something about it. Once rules are established, it would be nice to see the 1 to a slot.