Only "Sinatra In The Sands" was recorded with Jay Z though. Those other Jay Z features were tacked on after the fact. "The Scientist" was an unfinished Nas song where a Jay verse was later added. The Swizz track was from LIG and a solo Nas song with Jada and Jay added.
As for Def Jam era features, I think most of those songs will be songs we never heard mention of. The only other unreleased features are:
White Man's Paper feat Damian Marley
It could be interesting, be Nas's manager was trying to secure a Michael Jackson feature for HHID.