Ahhh, i thought they both died at the gate. I do remember readng years ago that nobody ever found his body so i'm guessing they will run with that as a finisher. Like you say though evidence is pretty weak.
Actually Spartacus and Crixus parted as they did here and he died separately.
The next episode seems to at least partially follow what Spartacus did after Crixus died.
Obviously not much evidence for this stuff. I reckon they will go for a defeat of Spartacus' AR,y but we don't see him die and he escapes with his roman poon.