I agree, with the one exception being that if Porzingis takes another step this year and looks like a potential franchise type guy, he + NYC could attract someone, and the free agents class is stacked next year.
Steph (hard to imagine any world that he leaves Golden State)
Westbrook
Blake Griffin
Probably Durant
Giannis (no chance he leaves Milwaukee though)
CP3
Rudy Gobert (would be pretty shocked if Utah lets him go)
Gordon Hayward
Kyle Lowry
Dennis Schroder (restricted)
Paul Millsap
Oladipo (restricted but attainable IMO)
Rose
Jeff Teague
Serge Ibaka
Steven Adams (restricted, probably depends on what happens with Durant/Westbrook)
Jrue Holiday
Greg Monroe
A bunch of guys will be restricted, but there will certainly be an opportunity for the Knicks to make use of their cap space next year, and it's easier to do so if you have space to bring in multiple studs rather than just one.