Upload & Sell: Off
Absolutely nothing wrong with any of these photos.......I really like #2 and the colors in #3 are simply awesome.
1. If you want to use super-high shutter speeds you will have to get more light, either natural or fill of some kind, onto the photo area, just boosting ISO won't solve the problem by itself.
2. An alternative might be to use a multiple flash setup, a single fill from a flash really won't get you there.