Sheriam did say stuff that she thought would give her some reprieve, but none of it mattered. Egwene mentions that the only argument was whether these women should be kept alive for interrogation.

If any had mentioned coercion, Egwene would have mentioned it, no? And unless their reason was something like Verin's, I don't see how the atrocities they performed in the name of the Shadow can be ignored. They deserved death.