Since snake's are fairly long lived, I'd sit down the whole family and show them pictures of both the hatchling and adult version of all the snakes you listed. Get a general idea of what intrigues the family, what you and yours feel you can handle and house properly up to it's full mature size and what in the end just makes you go "ohhhh I really, really want that one!". Then research that species to make sure it fits your lifestyle and what your expectations are. For instance most boa's will take a lot of handling more than most ball pythons will (within reason of course). However, boas generally have a longer and more aggressive strike/feed response (if that's a concern for you). Also consider your family's previous snakekeeping experience, sources for food for the snake that are convenient for you, etc.
The decision to purchase a snake and get the right one for you is important so it's great that your family is taking the time to do it right.![]()