The answers probably depend on what speed the riders expect, too. For instance, aero doesn't matter at all if both bikes are ridden on a rail trail at 12 mph. At virtually any speed, tires would be the first choice. Big fat knobbies have more rolling resistance AND more aero drag. For 17-20 mph speeds, I'd rate them as:
1. narrow slicks
3. drop bars
4. aero section wheels (yeah, they have to be 26" or maybe 650c depending on the frame)
2. clipless pedals
5. lighter frame
Frame weight wouldn't matter at all, except for startups and hills. (Geometry is another issue.) Moulton's claims about small wheels are pure hype. Consider the claims against the fact that he markets a line of folding bikes which use small wheels, and that to sell his bikes he must overcome the general public perception of small wheels belonging only on kids' bikes.