Laura, you didn't describe your outfits. Given that fact and that I was a CW 2-stepper - now ballroom dancer I can only give you some advice.
1) how much time between your various dances do you have? a few minutes? a few hours? a day? Should help determine if you even have time to change your costumes. 2)I'm assuming "slow waltz?" is CW Waltz? and two step is CW2-step not NC 2-step.
If you have little time for changing - I would suggest a dual purpose costume. One where the skirt is long but is part of the upper skirt/body which could then be removed allowing for your Rhythm/Latin costume to be seen. Ideally, it's two costumes that look and act as one, except that the long skirt can be removed. I typically use in the Nightclub dances, and CW - a costume where the skirt really swings and sways with lots of action that really shows your hip work and accents spins and pivots - this also works well for WCswing - not something that is predominately tight throughout the skirt area. Ultimately, the choice is yours. You can go to YouTube and type in some of the dances your concerned about and view what the competitors are wearing as a reference starting point. Have fun and good luck!