Ott won't want anything to do with Zucker as
@TheBoyDuddus really to try flipping him (not really worth it) , they are most likely going to buy out White this year.
The difference between Kapenen is 2 years in KK's favor, and a projected 12 pts (0.61PPG vs 0.41PPG) in Brown's favor last year and 8 pts (0.62PPG vs 0.52PPG) in the last 2 years (Kappy's time in Pitts). You might be thinking "oh, he played with Malkin, he should have had more points." Well, Kapenen played 45 games more than Malkin (7 games more y1, 38 y2). Career-wise Brown has a 0.486 PPG rate and Kapanen has a 0.474 PPG rate which is practically identical.
So essentially Kapanen is a super fast, 2-year younger version of Brown, who is slightly less developed. He can play PK just like Brown as well. In 321GP Kapanen has 5SHGs and 15PPPs, while Brown in 444 has 8SHGs and 30PPPs.
The difference in value isn't going to be much, so Brown for Kapanen+Legare (based off what
@Pags71 said about his high draft pedigree but yet to prove himself) or Kapanen+ a pick (could be a 4th up to a 2nd). Kapanen will likely want ~4m, so might be too rich for Ott. Brown is just 400k more than what Kapanen was taking in Pittsburgh, so getting him for 1 year might allow them more funds to use to keep Rakell around but not really lose much of what Kapanen brings other than his speed.
Watched both these guys on the Leafs btw, and at the time Kapanen was expected to have high upside compared to Brown. They are both pretty much fringe line 2 players now though.