I did not see Ms. Dickey but I did see Constance Carpenter on a Saturday afternoon in December of 1951, when Ms. Lawrence was ill. This was the first time I had seen an understudy in a major role, and I remember rooting for her. She was very strong, and Brynner worked very beautifully against her. The musical, then, seemed very much Anna's story---I know at times it can seem like the King's, but not at that point. When Ms. Lawrence left the cast, shortly before her untimely death, Ms. Carpenter took over and played the role for a long time Annemarie Dickey did replace her at some point in the run, I remember seeing her name in the adds.
Those pictures above do not look like Drake (I may be wrong) but he did replace Brynner for a while. Ironically, legend has it that he was originally offered the role of the King but turned it down because it only had one song.