I think it's par the course, as far as the UFC goes. Many of the contenders/champions got seemingly undeserved shots.
Rua got his shot after beating a washed up chuck.
Edgar got his shot before Maynard. after losing thier first fight he beat 3 ok-ish fighters to line up Penn.
Lesnar?... 3 times!
Hardy? beat 1 top 15 guy only.
Leites? Gets battered by Marquart and won via fouls.
It goes on...
I agree whole heartidly with your list with exception of Rua.... he's the best LHW in the world and PRIDE proved that. He didn't have a great start in UFC, but he was also injured and never did the proper path to rehabilitation to be 100% again.