I think you'll be just fine. I wouldn't make an ADR for later than 7:30 or 8 with younger kids, especially if they'd be bothered by the volume level (like my younger DD is - she behaves well in a quiet restaurant but takes a noisy one as permission to forget her inside voice).
We've been there late enough to enjoy the band and dancer's first set without any problems, and didn't feel out of place as there were plenty of other families with children. 7:15 is perfect timing in my opinion, because you should be there long enough to catch a bit of the entertainment right when it starts (at 8), but will have the quieter pre-entertainment atmosphere for most of your meal.