It's the sort of thing Caleb would say about himself. Actually, I think he has said it about himself a few times. Anyhow, it's a bit of an awkward switch since last week Nina told Brisbane that "there was someone here who wanted to meet me". I'm going to assume that this is an artifact of writing a story, one strip at a time.
Yes, if Kimberly were clever she'd sell him a quarter-interest in the firm, so she'd be the boss. You can't give him a majority, otherwise he'd probably sit around and wait for the ghosts to come to him.
This discussion was based on something that happened to me in real life; I just don't remember what. Kimberly is making up the "last time" here.
This proves that Kimberly is smarter than Brisbane, and that Peter is smarter than Kimberly.
So, what are Brisbane's intentions for Nina? Not sure. Considering that the contract fell through and Nina thinks that Brisbane wrote the note, his options are more open than they were when he met her. (yes, she's right about him writing the note, but she wasn't supposed to think that he wrote it).
Mercury pt 1 drawn by Cyber Hare