adopting older kids w/ biological children in the house - questions

We are moving ahead w/ the adoption process for a sibling group of 3. I am wondering about a lot of the little things at the moment. I have baby photos of my bio. kids hanging up in the house and also other momentos (we made footprints when they were infants, they have baby books, etc.). How have people handled these things when there are no baby photos or information to fill out a baby book for the adopted children? Is it right to take down/ put away these items? I feel like that may not be fair to my bio. children? I was thinking of doing something else that is special for the adopted kids and obviously hanging up plenty of photos for them too. Is this enough? I'm not sure what is really appropriate or fair to everyone in this situation. Kind of a silly thing to worry about, but it has been on my mind. :)