It depends on the horse honestly. Try a hack, if she does good use it. Or... try a bit, starting with a snaffle and if she does good then go with it. Its ultimately your choice and preference.
Some horses do better in certain bits or bitless rather than bitted but I believe if you have a truly respectful horse that it shouldn't matter what you ride in; Unless of course they just don't know and havent had the training, for example if they don't know how to yield to bit pressure, you can't expect it and they will likely try and fight it. You have to prepare her first and give her the tools to succeed. If you personally have not taught her something, don't assume she knows it. You need to get her responsive to the bridle pressure from the ground and teach her what to expect before you demand it.
As long as she is well prepared then you can use what you prefer
Exception to the rule is certain disciplines use different bits, etc... but the main point being a truly respectful horse with appropriate training can be ridden in anything
Good luck and Im glad to hear you and the kids are having fun with her Posted via Mobile Device