Some opinions aren't surprising, if a little disappointing. It never ceases to amaze the complacency that the status quo can create.
But moving on... in reading the RFP and a couple of articles it would seem like workforce availability, deal economics and ability to meet their schedule are the biggest deciders. If you just look at the percentage of the Houston workforce that's college educated or in a STEM field we lose pretty quickly to a lot of cities, but in terms of overall headcount working in STEM fields Houston ranks 7th nationally, and 4th if other west coast cities are ignored (I don't think they'll bother with another office in the same time zone). First place goes to NYC, then Washington DC and third Chicago. Dallas, Atlanta and Boston round out the next three after Houston.
I don't know where you find 100+ acres in New York, so that means you're looking at inhabiting existing buildings or new construction in a heavily heavily regulated city. Timing and economics become a concern. Washington DC has a similar set of concerns, especially considering height restrictions. Chicago could be an interesting option and appears to check most boxes, but the rust belt doesn't feel like the right culture for this company. Cost of living makes a big difference here...for a global company workforce is just a payroll liability and all things equal the talent pool is cheaper outside of the coastal markets.
In my opinion the top options after filtering for size of overall STEM occupation headcount (not percentages), regional availability of labor, cost of living, etc. make Houston, Dallas, Atlanta and Boston the most interesting case studies. Denver and Austin have a higher % of the workforce in STEM jobs, but they're 1/2 and 1/3 the size of Houston's employment base, respectively.
Flooding concern is a fleeting issue. Land prices will be a bigger concern.