Yep, many of us eat air-popped popcorn and corn tortillas. Dr. M said that although flour products are not recommended on MWL, 2 or 3 corn tortillas aren't too bad. And air-popped popcorn (so if that Whole Foods has no oil in it, it must be air-popping!) is also OK as a snack. I don't know what sweet mocha rice cakes are. You don't mean sweet mochi, do you? They look like 100% sugar! But if you do mean "mocha," I would look for dairy in there, and also watch the fat content.
Are you a label-reader? You'll need to be to do well if you plan to eat any foods that come with labels! (As opposed to potatoes, broccoli, oranges, etc., that have no labels on them!
) You'll be looking for calories from fat, and from sugar, and you'll be looking for sodium, too, which needs to be kept low.
Of course, popcorn, rice cakes, and corn tortillas are very calorie-dense, and should be used sparingly on MWL. If you find that when you have a lot of those, you don't lose well, that can be the first place you look--all those dried-out starches are very calorie-dense.