Spiteful's page

So I have a witch and a mesmerist in my upcoming game, and the witch really wants to take evil eye, but the mesmerist hypnotic stare ability says that the penalties from the stare don't stack with a witch's evil eye. So does that mean that if the mesmerist stares at a creature and gives them the -2 to Will saves, and a witch gives the same creature a -2 to AC with evil eye, only the mesmerist one applies, or does the term stacking only refer to an instance where the penalty is to the same type or roll, like if the witch used evil eye against the creatures saving throws?

Just got my PDF for Serpents in the Cradle, but I didn't get the interactive maps. Do I have to do something different to get them for this book of the adventure path?

I have a 3rd level sorcerer in my game who just got his signature spell feature (CRB page 193) but I am not sure how this will work as he continues to gain levels. Will he keep adding another signature spell each time he gets access to a new level of spells or does he just get the two signature spells for the rest of the game.