I think it's doable, but as others say, they may need a cab from OKW to the Contemporary.
It is possible to get out of the airport in less than 30 minutes; last time we flew in, we had a rental and we had luggage collected, rental car obtained, and were driving away in a half hour from stepping off the plane (and that includes the restroom stop once off the bird).
If they went from baggage claim to the taxi stand, grabbed a cab, they could go straight to OKW, which would take 20-30 minutes or so. Therefore, figure it's 5:30 (assuming they don't have to wait a long time for room keys or somebody waits to let them in). That's 45 minutes to get over to the Contemporary, which would best be done with either taking that same cab directly or just grabbing a bus to the MK and walking over (the walk from the bus to the monorail is probably as long as from the bus stop to the CR).
It's very doable, but there's really no time to waste.