That play session sounds lovely! I know what it's like to have standoffish hybrids, I have three of them myself and every little bit of progress like that makes my heart melt. I'm so glad you had that wonderful time with Millie, you really connect with one another by the sounds of it
I wouldn't worry too much about the cataract either, my hybrid Mint who has passed away of old age since had one in each eye and it never bother her or stopped her from living life to the full so I'm sure Millie will be alright too