New Orleans just traded Nerlens Noel AND next year's 1st rounder for Holiday. He's not going anywhere, let alone in a sign-and-trade for a guy that they can simply sign outright.
More importantly, Tyreke can be a sure thing. Match the offer sheet and he's a King. With Iguodala you're competing with half a dozen other teams, including the Nuggets who can exceed the cap to sign him.
As I said in the other thread, if the Kings could really clear the capspace for Iguodala while keeping Evans, they'd also have the room to sign Dorrell Wright and Dalembert instead. Personally I think a Reke/McLemore/Wright/Cousins/Dalembert lineup with JT/Patterson and IT off the bench would be competing for a playoff spot next season. AND you'd likely still have a couple trade assets (Jimmer, Thornton, Patterson if they weren't dealt for caproom already) and some dead money coming off the books in a couple years (Outlaw, Hayes) just when Dalembert's deal should also expire.