There are a few schools in the Dallas area that have a fairly large number of asian students.
Things to keep in mind is that Phoenix, Dallas and Florida are Hot in the summer. At times flight training will take place during EARLY mornings and late evening. The Portland Oregon area weather doesn't have the extremes as some other areas. I lived in the area for 3 years. There will be days of poor weather, but that is also true of every place else on your list. Plus no hurricanes, almost no tornadoes, no tropical storms, few severe thunderstorms. Plus you get some mountain flying experience.