Howdy,
I'm here just to give my two cents as my Father and I have been involved in weddings for quite a long time. (We're those guys at the back of the church that just stand there that nobody ever notices) Anyways, my comment is about the sgian dubh. It would be absolutely proper to ask the minister/priest permission and don't be surprised if no is the answer as it is an unwritten rule that weapons (show or otherwise) are not allowed in the Lord's house. I've dealt with military, police and plenty of Scottish/Celtic weddings in the past where there is an area disignated for the "keeping" of the weapons. The surprising thing is at 90% of the kilted weddings the men ask for an area to "lay down their arms" on a traditional standpoint.

Anywho, do what you want.

Cheers,
T.R. Matthews