Moderate isolation or bagging recommended. Banana Supreme is a hybrid. The different species of squash don't cross. You'll need a book to know which are which. But, isolation is very easy to achieve.
Celebrity is a hybrid.
Seed can be saved from non hybrids. Territorial Seed Company , Cottage Grove, Oregon, USA 2. Henry Field's Seed and Nursery Company , Shenandoah, Iowa, USA 3. Hand pollination of squash. If you want to try saving seed, beans and squash make it easy to get started.