The whole concept of the mezinka was in fact taken from not frum concepts and with the passage of time people became less concerned about the idea and it became more acceptable. Unlike Joseph however I know you were never in a million years planning to have mixed dancing.
The reason many Rabbonim are against the practice aside from the origin is what takes place during the dancing. Many choshuve rabbanim feel it is against Jewish ideals to show that you have now swept your kids out of the house on their own. A Jewish parent should always demonstrate that the house is always open even if the child is married on their own, and mommy and daddy are always there IYH especially when they become bubby and Zaydie and that parents always show concern and have you in mind in their tefilos .
A few Rabbonim that I have heard directly from have said that a Jewish Parents Job is never done, by demonstrating a dance with the broom it is as if you are showing you did your job to marry off your kids to send them off into the world and now you can be patered(exempted) from your kids lives.BH it is a tremendous accomplishment,and should be celebrated and obviously not all rabbonim feel this way. Everyone should have Yiddishe Nachas and may you have mazel and Bracha whatever your decision.
In the Zchus that you are thinking of your friends may your friends always think of you