I like the idea of the deck and have built one similar in standard.
Lotleth Troll may be worth considering as it allows you to discard creatures you don't need/want to power itself up. I'd probably replace
Trestle Troll with it.
If you want to make full use of the creatures in your graveyard you could use Varolz to give each creature Scavenge. If you add in Death's Shadow with Varolz you can get 13 +1/+1 counters for 1 mana.
Corpsejack Menance could also help with the +1/+1 counter theme, allowing you to grow your creatures and sac them to Jarad for a huge life drain.