Both teams would jump on the trade, especially if we add some spare 1sts for him and O'Quinn
What are you talking about? Porzingis is the only untouchable player on that entire roster. The Knicks have made it clear by repeatedly trying to talk Melo into voiding his no-trade clause that Porzingis is their building block. The odds of actually hitting on a superstar with the number 3 pick are about 15%... That's why it's so stupid to trade down from the #1 spot where the odds of drafting a superstar are more than twice that.
Let's look at the last 20 years of draft picks
Since 1997 3 superstars were drafted at #3 overall Carmelo Anthony, James Harden, and Pau Gasol.
2016 Jaylen Brown
2015 Jahil Okafor
2014 Joel Embiid
2013 Otto Porter Georgetown Washington
2012 Bradley Beal Florida Washington
2011 Enes Kanter Kentucky Utah
2010 Derrick Favors Georgia Tech New Jersey
2009 James Harden Arizona State Oklahoma
2008 O.J. Mayo USC Minnesota
2007 Al Horford Florida Atlanta
2006 Adam Morrison Gonzaga Portland
2005 Deron Williams Illinois Jr. Utah
2004 Ben Gordon UConn Jr. Chicago
2003 Carmelo Anthony Syracuse Fr. Denver
2002 Mike Dunleavy Duke Jr. Golden State
2001 Pau Gasol Spain Memphis
2000 Darius Miles HSSr. LA Clippers
1999 Baron Davis UCLA So. NO Hornets
1998 Raef LaFrentz Kansas Denver
1997 Chauncey Billups Colorado Boston
What you get at #3 is a wealth of guys who range from serviceable NBA bench players to all-stars, but arguably only 1 or 2 guys you'd actually build a team around.
This is basically why the Knicks would be insane to trade Porzingis for anything less than the first overall pick. They already struck lottery gold with him. They'd be taking on a MASSIVE risk that they wouldn't get anything near his value in return.