I killed Alice McLafferty and Gloria because they were being smarmy and I didn't like them.

Now I can't recruit Cass, even after going through all her dialog twice over, leaving, returning, and doing it again. Whats up?

Console commands dun work on PS3, so that isn't it.

You failed her recruitment quest by killing those two prematurely. Load a save before you did it, otherwise there's no way to get her.

Shucks.

To late for that. Never found her interesting anyway, just wanted to fill up the Lucky 38 Suite with all companions

How could you find her interesting in the first place unless you actually recruit her and talk to her?