Yeah, I'm pretty sure Kim and Chelsea are grooming Kat to go to the Final 3 with them and not Sabrina.Although to people looking at them on the outside, it must seem that Alicia, Christina and Tarzan should have joined forces with Leif and Troyzan, we're not there and we aren't seeing the whole picture. And I can see some reasons why at least Alicia and Christina failed to bite.
First, Troyzan is a known challenge threat and Leif is a likely jury threat because he's a little guy and can get sympathy votes. Although I doubt that Leif would face the jury, I'm not sure that Alicia and Christina would want to risk aligning with him and Troyzan.
Second, I suspect Kim has Final 3 deals with Alicia and Christina as well as with Chelsea, Kat and Sabrina. If I'm right, why would Alicia or Christina have reason to switch? They each think they're Final 3! After all, one reason why Rick and Edna failed to switch things up was because they each had Final 3 deals with Sophie!