Sequitors are better in every way and especially in path to glory as you don t pay more points for them nor do you require the lord arcanum tax to make them battleline
From the blades of khorne faq:
Q: When Skarbrand becomes Incandescent because he was
not able to fight in the last battle round, does he use the
Incandescent row of the damage table to determine Slaughter’s
attacks and Carnage’s total carnage rolls?
A: Yes.