It takes along time to get a bird to accept new foods. We have tried several but she refuses to try them. I keep trying and so does DH from time to time. He gives her apple and crackers most days.
I had a green headed conure for awhile but it came to me mean and I think it had been mistreated. I found it a better home.
You do want to watch your two Sadie as when I had two cockatiels who were brother and sister and they bonded as mates - I tried to seperate them and I came home one day to find Petey( who became Petra when we found he was a she) had pulled out blood feathers and she had blood all over the place. I had to put them back together. So go slowly and watch to see if they will both be alright apart.