here is how it would play out:
Mottram would have to ride 40,000 miles in order to get the base to ride a strong 112mi. Lance would need to get back on his bike for 6 months to be 95% of the cyclist he was a few years ago.
Lance split 15:17 and 15:42 at a duathlon back in 1990. He can run.
If Lance decided to do 2009 Ironman, he could swim 55 min, ride about what Normann Stadler, or whoever the fastest rider would ride, then run a 3:10 marathon. This is assuming that he had the focus and same type of program he was on during his hey day.
If Mottram did the same event, I could only say that he would not run faster than a 2:40 marathon. The swim, bike, heat and humidity is an equalizer.
I remember when Barrios claimed he could run a 2:20 off the bike at the end of the Ironman. It would be a miracle if he could have run a 2:20 solo in Kona, assuming he started his time trial at 1pm in the sweltering heat on the Queen K.