ow let me throw another consideration: cargo size and weight.
If my calculations are OK, the Yak has a 120-L bag and the 2-wheeled Burley Nomad has a 160-L capacity. Large panniers like Arkels touring series offer 54-L rear and 38-L front (GT series). for a total of 92 L... plus whatever you want to put on top of the rear rack. If one of you prefers to ride with panniers and the other one with a trailer, one solution might be to have one person carry the heavy and dense stuff in panniers (i.e. repair gear, food...) and the other one carry the light and blky stuff like clothing in a trailer.