Didnt read the dune-books. But i saw dune in the TV.
#1 Dunecat
#2 Hellcat
#3 ...?
how about pinkpanther!?

If you like to read sci-fi, definitely give Dune a try GiantMelon.
Maybe a proper Kzinti name for your third character? Kzinti naming conventions are rather unusual. During a lifetime, a Kzinti can have many different names, most of which are descriptive of the Kzin in some way. A kzin must earn his name. For example, in one of the best stories, there was a cowardly Kzin who was named Eater-of-Grass by his peers. The name was terribly insulting because it pointed out not only his cowardice, but saying that he was a herbivore....unthinkable!

But that was his name for a number of years.
As a Kzin moves up in society, names generally follow this convention:
1. When a Kzin is born the only name he is given is his birth order and father. For example, "Fourth son of Hraak-Riit". This is partly due to the fact that many Kzin dont survive past being kits, because the weak and slow are devoured by their litter-mates. So giving them a proper name does not make much sense to the Kzinti.
2. A Kzin will usually be come to be known by his profession when he goes out into the adult world, and also by his planet of origin. For example, a Kzin might be called Builder-of-Starships from Hssin.
3. A Kzin that attains a military ranking has earned the right to a real name, and his rank designation. For example, Hraak-Seargant.
4. A Kzin who has risen further in the social hierarchy goes simply by his one given name. Example, Hraak.
5. A Kzin who reaches the highest levels of society uses both his given name and patronymic family name. Example, Hraak-Riit.
So a Kzinti could be named almost anything that is descriptive of the Kzin's personality, profession, history, rank, family, actions etc. So its fun to be creative and come up with something interesting.

As it should be

No the last 2 books aren't as good. The Gholas storyline was a bit over played. Careful though, unkind words about Dune and I'll send facedancers after ya....