I missed your thread earlier....but I am excited for you! Your are brave taking on 3 that young, but I have seen with my 2 that are 14 months apart that sometimes it is easier. They are best buddies most of the time, and if I take my 2 year old somewhere without little bubba, she spends half the time asking me "where's bubba?".
I think it will be good that the older 2 are male and female. If it does lead to adoption for all 3, I've heard that when they get a little older there is less sibling rivalry with opposite sex kids that are that close in age. And a 2 week old......time to snuggle
! Can't wait to hear how it goes.