R.S.
First of all, ignore comments like Julie T's...what a joke.
My son is 2 1/2 and LOVES his pacifier and like yours, only uses it to sleep. My 6 month old daughter LOVES her pacifier and will use it whenever she needs it. Some kids just need it, and both of mine do. I struggled with whether to take it away from my son before my daughter was born and I'm glad I didn't. I used to worry about what it meant if my 2 year old still had a pacifier but you really learn to just get over it and do the best you can. Even though my son only has his "baboos" while in his crib he has never tried to take my daughter's. I don't feel like its such a bad thing if they only use it to sleep and we're planning on getting rid of it by the time he's 3. Perhaps around the holidays we'll do something similar to the DIsneyland idea. I think once they're old enough to understand that they're really "big boys" and can exchange it for something then the transition will be easier, as opposed to just taking it away when they won't really understand why...especially if another baby gets to have one.
My advice is to just let it go for a while longer. With an 8 week old baby you have enough to think about and the transition for everyone is enough as it is without taking away one of the greatest "soothers" they have. Don't let people make you feel guilty...you know your children best and in the whole scheme of things its really not that big of a deal.