Welcome to BP.net.
I know it is a lot to absorb, all these changes we are telling you to make, but we really do have the best interest of your snakes and yourself in mind. Sad to say most pet stores know little to nothing about care for most of the animals they sell. And books can be a good source of information but you have to check and see when they were published. A book that is even 5 years old can have mostly outdated information, and I see many books out there that were published 10 or more years ago.
Take it one step at a time, do separate your snakes. Take steps to monitor your temperatures and humidity properly, give your snakes time to adjust to the new surroundings, then don't be afraid to feed them in their enclosures, it doesn't cause cage aggression, and will probably improve their feeding habits.
Handle them gently, I try not to handle for more than 10 or 15 minutes at a time. And of course you shouldn't hold them for about 2 days after they eat, to avoid any problems with stress and possibly regurging their food.
There is much excellent information here for you to read and study, and we will always be happy to answer any questions you may have. I look forward to getting to know you better and watching your snakes bloom under good care.
Gale