If that is your Ada in the 1901 census she sure did find a good family to live with and to look after her. As you know the majority of them were abused of some sort. If that is your Ada 1901 she also used her guardians name on her marriage certificate. How to prove that is another story. thru your searches you'd have to find a connection to the Markham family. I believe you mentioned Clark - there were 2 Clark families both with an Ada - a John and an Albert Clark family. For now GAIL (PS are you in Ontario?) PSS our adoptions prior to 1921 were looked after by FACS - it might be worthwhile checking with them?