I think by far the best guage to determine what cities will be played in the fall in North America is to go back to the original itinerary that was leaked in December. I would assume that the plan will be to play those cities that already were planned for then, plus they'll add in the cities originally scheduled for March that were lost due to the entire first leg being rerouted.
In looking at the original fall leg we can assume they'll probably play shows in the following:
Originally scheduled for third leg and not being played on first leg:
Toronto, ON
Minneapolis, MN
Milwaukee, WI
Cleveland, OH
Washington, DC
Pittsburgh, PA
Auburn Hills, MI
Houston, TX
Dallas, TX
Las Vegas, NV
Albany, NY (optional city on original itinerary)
Sacramento, CA (optional city on original itinerary)
Returns to cities played on first leg and also listed on original third leg:
Chicago, IL
Boston, MA
New York, NY
Philadelphia, PA
Anaheim, CA/Los Angeles, CA
San Jose, CA/Oakland, CA
Cities originally scheduled during March on first leg, but left off:
Miami, FL
Tampa, FL
Atlanta, GA
Hartford, CT
Buffalo, NY
Montreal, QC
That should roughly end up being your list of cities visited on the third leg. You can continue to speculate on cities like St Louis and Kansas City, but they appear to be doubtful. Those cities were only added to the Elevation tour as an after thought when the ending of the tour was extended from 11/19/01 to 12/2/01, so expect them only if U2 end up playing all 3 months of the fall leg in North America.
You have to consider that contracts would have been in place between U2 and tour promoters TNA with arenas throughout North America and I'm sure they fully plan to honor those before they even consider adding extra cities not originally planned. Arthur Fogel of TNA stated in the current issue fo Billboard that they plan to return to many of the markets they feel they have vastly underplayed on this first leg, so expect multiple shows in the 6 major markets listed above for return shows.
The third leg in North America was to have run from Sept 16 to Nov 10 before heading off to Japan. They now have about 2-3 weeks of shows that need to be added onto the fall leg in North America so I think Japan and Australia will not happen before December at the earliest, January more likely.
Perhaps if time permits U2 will add additional cities to the fall leg, but people in cities not listed in the original itinerary should probably keep in their minds that they may have to travel to see U2 this fall. I guess we'll all know for sure in about 5-6 months when they announce the fall tour leg.