Kudos to you for putting in the time and effort to be prepared. That will make a huge difference when bringing the animal home and sets a great example for your kids. Two thumbs up.
If feeding live is a make or break, you definitely don't want to bring home an adult snake who has refused F/T. Chances are it will take months or longer to transition to F/T.
Adults are also prone to refuse food for a while after being moved. Probably not the first snake experience (as a permanent pet) you're looking for.
My two cents would be to check out morphmarket.com and do some "window shopping". You will find tons of BPs for sale. Just do your homework and find a reputable breeder. Or at least get some ideas in mind for the next expo.
Since live feeding is something you want to avoid, your best bet will be to find a juvenile from a reputable breeder that is already well established eating F/T. By well established I mean AT LEAST 5 meals of F/T without refusal.
I just think this route will be more enjoyable for you and your family while also eliminating any concerns about feeding live.
Good luck! Please keep us posted.