And, like you said, the tax doesn't matter. The only problem would be that the Knicks can't do sign-and-trades that year as a tax team, but that's a risk they're willing to take that 1 season. In the 4th year, like you noted, everyone else's contract is expired.
It's telling that, essentially, Melo, STAT, Tyson, and Lin have 3 year contracts. That's their window.