Hi there, Nicola!
Downtown Disney at night is definitely a lively place, full of options for shopping, dining, and having fun. There's always something to see: people-watching, street entertainment, and just soaking in the general ambiance.
You are welcome to find somewhere to rest for a while, and the children can certainly bring handheld video games to keep them occupied.
There a few areas with seating alternatives for Guests, but the objective at Downtown DIsney is to explore. It might be fun to alternate shopping with relaxing: something for everyone. In fact, you grown-ups might get so caught up in the environment that you won't want to sit still!
Have a wonderful trip!
See you later, celebrator,
-Deborah B.