Hopi blue corn is, in fact, a race of corn known as flour corn, so yes, that would be flour. Stone ground meal is usually dent corn or, if you're in New England, flint corn. In fact, in Rhode Island, if you're going to make a johnny cake, you had better be using white cap Narragansett flint corn, or it won't be considered acceptable.
There are a ton of things to do with stone ground corn meal. Johnny cakes, hasty pudding, corn meal mush (which is at heart close to the same thing as polenta), corn meal pudding (if they have my book, Midwest Maize, at your local library, I have a great recipe for corn meal pudding in the recipe chapter), and, of course, corn bread. Stone ground corn meal takes longer to cook than the steel roller-ground stuff, but it is "cornier" and heartier, and most fans of corn consider it worth the trouble.
Keeping it in the freezer is good -- as corn can go rancid. But, again, it depends on the type of corn. Flour corns do go rancid faster than flint corns.
Happy cooking.