Hey, I have twins too about the same age: girls at 21 months. They are a handful, and on the plus side, that does help burn calories, right?? Well, when I was losing my twin baby weight (before I got pregnant again

) I stuck around 1400 calories and exercised in the morning before they woke up. It was almost impossible for me to do exercise during nap time back then because they had different sleep schedules. But that worked well for me and I would lose 2-3 lbs a week typically.
It sounds like you have a good plan! Especially dancing with your boys! I do that with my girls too sometimes and it really helps to just relieve all the stress of the day and they feel like they get more attention, too. Just keep track of what you are doing and eating and in a week or two, you will be able to see when you make the most progress. Good luck, and this is a great place for support!