Do you think they will use the same facilities as the World Cup to give them a practice run, or will they utilize other cities that did not get World Cup dates?
I don't really think the facilities need the practice run, given that they host other events. It's a little different than World Cups where the host countries are building new stadia.
That said, Copa America Centenario was hosted at the Rose Bowl, MetLife (NYC), NRG (Houston), Lincoln (Philly), Gillette (Boston), Levi's (SF), CLink (Seattle), Soldier (Chicago), Phoenix, and Camping World (Orlando). NYC, Houston, LA (different stadium), Philly, Seattle, SF, and Boston will all be hosting WC26, so there may be some overlap.
For the Centenario, they required a minimum capacity of 50K. So, if they wanted to use 10 different hosts to "spread the wealth", they could also do any of Chicago, Phoenix, Orlando, Charlotte, DC/Baltimore, Austin, Cleveland, Cincinnati, Columbus (using the Horseshoe), Detroit/Ann Arbor, Indianapolis, Nashville, Pittsburgh, Minneapolis, Milwaukee (Green Bay), Memphis, New Orleans, Tampa, Vegas, Jacksonville, Buffalo, St. Louis, or Denver, off the top of my head.
My guess is that cities without an MLS team wouldn't be considered, so rule out Cleveland, Detroit, Indy, Pittsburgh, Milwaukee, Memphis, New Orleans, Tampa, Vegas, Jville, Buffalo.
My guess is they wouldn't want to play in a dome, so that would rule out St. Louis and maybe some of the others, idk enough. So synthesizing everything, the 10 could be, without overlapping with WC cities, DC/Bmore, Chicago, Phoenix, Orlando, Charlotte, Austin, Cincinnati, Nashville, Denver, and Minneapolis.
You could have nice pairings: Chicago/Minny; Denver/Phoenix; Austin/Nashville; Charlotte/Orlando; DC/Cinci.
But who knows. All this really shows is that I'm procrastinating at work.