S.C.
I have 6 kids. I suggest you let the older to help with the baby in little ways. If you breastfeed it is easy to read a story while you are feeding the baby. As for sleep it is easiest to just sleep with the baby. If you put the baby in with her sister then don't do the cry-it-out thing. I would just relax and enjoy the baby. everyone's routine will change some when the baby comes. You will find a new normal. I have found the more I roll with the punches the more fun parenting can be. All children will eventually sleep on their own so I would not stress too much about the sleep thing. No one goes to therapy as an adult because their mom rocked them to sleep too many nights or held them too much it is more likely a lack of holding and hugging that leads to future emotional and social issues.