"I want to know how much a role a Protestant Minister can participate in a catholic wedding?"
I have read a couple posts on this topic and I think the answer comes down to: depends on your Presiding Priest/church family and how they do things in their Parrish.
I was most close with my late grandfather, once he passed away I began to look up to his brother, my great uncle. I would LOVE if my great Uncle Jim (The Reverend Doctor...) could 'marry us'. However, I know being that being within the catholic faith, a priest must ultimate bless the marriage. Does this mean, the priest must, at minimal, head the vows? Could my Uncle do the sermon?