If Lulu hooks up with anybody, be it as a permanent thing or (more likely) as a Lulu-gets-depressed-girl-comforts-him-and-they-wind-up-fucking deal, it'll be CC. He's not remotely close to anybody else in the series like he is to her.
Kallen probably has/had a mild crush on Lelouch (despite his deliberate efforts to make her hate him in order to throw her off the trail) and a fierce loyalty to Zero, and is likely jealous of CC for being closer to him than she is, but I don't think those all combine to a straight-up romantic interest in him- there's a bit of that, yes, but the big picture is a bit more complex. And of course Lulu doesn't see her as anything more than one of his most skilled/reliable subordinates. I really don't see their relationship changing all that much beyond what it is now, aside from maybe Kallen's feelings going more in the romantic interest direction.
Kallen x Suzaku is... obviously a possibility given the island episode, but I really can't see the plot going into a direction that would allow this one to develop either, given that Suzaku's clearly on the Brit side and Kallen's clearly on Zero's side. Then again, we have 20some episodes to go, and this is a Sunrise show, so I suppose anything could happen.