Yes: there is a property that can be set for the slider components that suppresses item updates until the slider is released. See releaseOnly in the docs:
No: the slider that you see on that item’s detail page is the default stand alone widget for that item. I don’t think you can change the releaseOnly setting on that widget. However, you can define your own new default standalone widget for that item and then you can include in that custom widget the releaseOnly property.