House Decor that require quest completions question

Hey folks, merry xmas, I went off exploring to get house decor and noticed most at least in the old zones require quests completion. Even though my account is from 2004, apparently I didn't complete alot of these older quests that disappeared after Cata I heard?

So my question is, are we supposed to make a character in Classic and complete all those old quests? I guess it stops at Cata, and then the rest I can do in retail post Cata?