Hi D.. The best way to lose weight and keep it off is by losing it gradually--like 1/2 to 1 pound per week. To do this, you need to be in a calorie deficit of about 500 calories per day. What works best for lots of people is to burn a couple hundred extra calories per day (above and beyond your normal activity) through exercise, and delete a couple hundred of extra calories from your diet. For example, adding a two mile walk and subtracting a can of pop and a cookie.
There is no magic bullet for exercise or food. Choose exercises you will do consistently because you enjoy them. But, the classes/exercises that burn the most calories are aerobic in nature and are weight bearing (on your feet). Pilates, yOga, and stretching are great, and they can make you stronger (and if they relax you, they may help you not overeat or engage in emotional eating), but the moderate-to-higher intensity classes burn the most calories per minute, which is important if you have limited time. Also, you may have heard that weight training and building muscle burns calories at rest. THis is true, but for women, the effect is less than it is with men. So just because you are "building muscle", do not worry that you will "bulk up", or need to drink power protein shakes. Women don't have enough testosterone.
Good luck! J.