I would stress, for the people going to the summit, that they learn about the effects of the altitude, and the symptoms of AMS. Although some people are not affected at the 14,500 elevation, a majority are. Some are really hit hard just after 12,500. That being the case, I would highly recommend acclimatization, the best would be to stay two nights at Horseshoe Meadows (10,000'), a walk-in campground area about 35 minutes out of Lone Pine (Start up the Whitney Portal road, then turn south). There are some nice conditioning or warmup hiking opportunities there (Cottonwood Lakes, Cottonwood Pass, Trail Pass & Trail Peak)
Woody, big ole ditto to that recommendation by Steve. Experience at altitude and acclimation plans were the two big questions that jumped out at me. These guys may be exceptional endurance athletes, but that means little to nothing if altitude sickness (AMS) grabs hold of someone. Many strong, confident marathoners have been humbled by high altitude, and the majority of the research indicates that there's just not a lot of correlation between conditioning and the propensity to avoid altitude issues. Spending a couple of nights at or above 8000 feet before the ascent should be a very high priority. Either that, or have lots of Diamox on hand.
If someone is hit hard by AMS, it's really not a matter of just sending them back down. For safety's sake at least one other person should accompany them. The symptoms can be brutally bad and come on quickly, compromising the person's ability to negotiate a descent safely by themselves.
