I'd use a flash, and film ISO 400 or slower. I also wouldn't worry too much about the "Leica request" except maybe in a church whre sound may be a problem. At reception... there is likely to be som much noise and excitement that nobody would notice even a really loud camera (like a Hasssssy).

For color negs... Porta, for sure.

For B&W... Ilford.

One camera for each.