Outdoor rabbits tend to live much shorter lives than indoor bunnies. I recently read a House Rabbit Society poster that estimated the lifespan of an indoor pet rabbit at 8-12 years and an outdoor pet rabbit at 2 years. It can be more difficult to notice signs of illness (especially since rabbits, as prey animals, are so good at hiding their symptoms) when they're not around you so often. Also most rabbits don't tolerate extremes in temperature well and can die from heat exhaustion very quickly, even if given adequate shade. I don't know where you live, but most areas are intolerable in the dead of winter and the heat of summer for outdoor rabbits. Not to mention the fact that rabbits stress extremely easily and can actually die as a result. There are many stresses outside that a caged rabbit cannot escape from, such as animals outside of the rabbits' enclosure, dogs barking in the neighbor's yard, planes, loud trucks, ect. I recently read of two rabbits who contracted rabies after a raccoon attacked them through their wire enclosure. And I saw another at the vet who was killed and decapitated by a wild animal, taken from an enclosure that was supposed to be safe.
I don't mean to come of as rude, I just wanted to share some facts from what I've read and seen personally. I hope that you'd consider keeping them indoors. Clearly you're doing your research and trying to offer a great home, and that's so extremely important before bringing an animal into your life. I wanted to share the information so you can make an informed decision when you opt to keep them indoors or out.