Well, it is truly non-trivial to find a linking theme between the two Solaris, His Master's Voce and Cyberiad. At least, the matter becomes complicated when we're trying to incorporate Cyberiad into the idea.
However, everything is not lost. Notice that in Cyberiad we're encountering the fables and stories about robots, but they're written exactly like they were human-stories. More, they are based on the medevial language forms and ancient legends, laced with great humour. What it shows, is similarity between humans and robots (as Lem imagined them). Therefore I would try to base on the idea of philosophical anthropology. By which I mean:
1. Lem views robots as humans, and describes them as people. It is a substantial simplification, which makes the story rather funny that serious. However, it is the ONLY way to give the human reader an insight into the robot-life. Or isn't it?
2. Humans imagine alien inteligence as human-like (with all the consequences).
3. Humans try to communicate with other inteligences like they were also humans (with all the consequences).
Here, link this now.
Best Regards
Terminus