I’m a little shaky on abilities and triggers so hopefully someone can help me out. Say my only creature in play is Tergrid, God Of Fright and then I cast Pox. I know I’d get 1/3 of permanents from opponents discarding. Would I still get 1/3 of my opponents creatures when I myself have to sack tergrid and she is no longer on the battlefield and they all hit the bin at the same time? I don’t believe I get their lands since that part of the spell resolves last and she would be gone.
Anything sacrificed at the same time as Tergrid will still cause Tergrid to trigger. So, you seem to have it right: You get the cards that are discarded, then you get the creatures sacrificed, then you will *not* get the lands since that happens after creatures are sacrificed.
Tergrid and Pox