Depends on the trailer. MOST of the older double trailers, I would say no. But a bigger trailer, meant for 2 new 4stroke skis... sure... they can hold the weight. But as above... verify the axle, and tires are up for the job.
It's close... but it would be legal. Max lane width is 8.5'. (103") The '96 XP is 100" long.
It would be harder to load and unload since you would have to put the trailer in enough to get the rear ski off... then back up more to get the next... and then the third. When they are in a line... you can float the rear skis, and just pull the third.