You may want to use dry ice. Dry ice hovers the ground like early morning fog. Dry ice works well in warm water and using a dryer vent hose and a blower, it should work well. I would fog it up, then let the guests in. If you have a theatrical stage lighting or sound company in your town they may have a dry ice fogger machine for rent. The machine is made using a 55 gallon drum with a heating element to heat up the water you fill it with. It also has a blower on it and an outlet to connect the dryer vent hose. You put the dry ice in a basket and lower it into the warm water just like you would lower french fries into oil. You would then lower the lid and turn on the blower and you get fog. I hope this is helpfull.
Good Luck with the wedding,
Scenic Art Productions