So both of these archetypes grant the slayers studied target which increases the DC of "slayer" class abilities. OF course, these classes also cast spells which are class abilities. So, do the DC's of the spells cast by these archetypes increase for their studied targets? My read is yes they do, but what does everyone else think? Has there ever been a FAQ on this?
I don’t think there’s anything official and that could be read in lots of different ways. For instance, you could say that spells are not class abilities, rather your class ability allows you to cast spells. There does seem to be a trend in the rules to address spells and abilities as separate things.
The sanctified slayer has been around a long time, (it's in the ACG) surely someone asked this question and got an answer...