Xrhrft

In a case of a Ger/Convert, what role can non-Jewish parents play at the wedding ceremony?

Halachically can the parents accompany their child down the aisle? Could they stand under the Chuppa?

Any sources on the topic would be much appreciated

I was involved with someone who had the following situation (I don't know the sources involved in the decision, just the guidance that was given. HaRav Tzvi Berkowitz was the Rav being consulted):

The groom of the father was Jewish, but his mother was not, and the groom had converted. However, it was not publicly known that he had converted. The parents of the bride were divorced. Some consider it a bad siman for a divorced couple to walk the child to the chuppah, and therefore it was decided that the fathers would walk down the groom, and the mothers would walk down the bride. However, this left the bride being walked down to the aisle by a divorced woman and a non-Jew. Therefore, an older couple who were very close to the family of the bride walked a short distance behind the bride to escort her to the chuppah. The older couple veered off before the chuppah, and the groom and bride both had their parents with them under the chuppah.

I included all of the details so that I wouldn't be misrepresenting anything, but peeling away some of the complications, it does seem that a) if non-Jewish parents are walking a child down, it would be better to have another couple be co-escorts, which can be done by following behind, and b) a non-Jewish parent can stand under the chuppah with their child.