I am thinking that you have already worried more than any anxiety or stress your kids will ever have. I have a 4 1/2 year old, nearly 3 year old and 11 month old. The two oldest adore their baby sister and take such good care of her. They are always looking out for her and are very protective. My biggest advice is keep them involved wherever you can, kids love to have some responsibility - especially when they can help mommy. The biggest anxiety my older son showed was he was visibly upset a day or two after the baby came home and when asked what was wrong he started crying and told me he just wanted to "hold her". Well we sat right down on the couch and held her together and looked at her. His attention lasted about 30 seconds before he was up and running off to play. LOL. Remember to take the time for yourself to heal (it is hard to do when you have two others at home- i was off and running too soon). And give them something to do when you are feeding/nursing. So here are some things that I did, maybe they will work for you...
- kept a stool by the changing table as my daughter wanted to partipate in changing diapers. I would give her a toy to shake.
- when giving a bottle, often had one of my kids run it out to my husband. They always thought this was really important - even bickered over who got to do it.
- let them have access to the baby, obviously, make sure it is in a safe way, but the more access the more they feel part of it.
- Overall keep things easy and low stress. They will react the same
- Bedtime routines, story times, all the key things which were part of my older children's life was teh same. If I couldn't put them to bed because I was nursing and daddy did it - he told them I would come in and say goodnight as soon as I could.
- Do what you say. If you tell them you can't do it right now because of the baby, make sure you follow up.
- we had each of our kids pick out something for the baby themselves. It was not special trip, just when we were out and about. One of the toys was for older babies, but it meant something to that particular child as it was her favorite character. They felt much more important and valued doing that than us picking something out for them.
- you really can't make a mistake and if one morning/day/etc goes wrong, there is always the next day.
Good luck - the third one just slides right in....