New Years Day we will be heading over to Kuki'o Beach for the ceremony (probably around 1) and then the "reception" will be the Island Breeze Luau.
Hotel - I am still trying to work out a group rate but I am currently looking at either the Sheraton or Marriott, both are on the water and in downtown Kona so there is plenty of places to walk to and they are central to most activities around the island.
Plane tickets should go on sale in December / January. For best prices I would say book quick because we are going at a prime time. We will be going over on Friday December 27th and coming back on Friday January 3rd. (If there is a big price difference these dates may change by a day or two one way or the other.