I was so sorry to hear about Robin.

Only advise I can give is for sure see if the cats could meet before adoption. An older grown up cat might be less apt to want to play and jump out and startle Jackie. My cat Grandma has gone blind and she gets upset even by my voice so I keep her in my bedroom so she can have peace and quiet. Of course she is a real oldster now at 17 or 18. She does not seem to miss being with other cats.