I would guess no you cant sac a thrull
as you play symbiotic wurm
i would think they all come into play at the same time. Endrek will still fit nicely in here though, even if he dies you can use debtors knell to pull him back out once you get the thrull
count down a bit.
As for savra shes just icing on the cake to go with grave pact, but not really necessary. Nice to have the option when sac'ing creatures to do her ability too tho.
Dont see your infinite loop, whats the combo?
Looking better up to 8.5 or so .
Always happy to give advice, just ask on any of my decks and ill try to get back soon. -Will be inactive for a while-