Uru Zil'Jain's page

The question is in the title: Is the number of skill points per level a class feature?

I'm asking because of one class feature of the Seducer archetype for the Witch from Legacy of the First World:

A seducer’s power comes from her

allure. She uses her Charisma rather than her Intelligence
score for the purpose of all class features and effects related
to her witch class, such as bonus spells per day, the maximum
spell level she can cast, and save DCs of her spells and hexes.

Does that mean a Seducer gets 2+Cha skill points instead of 2+Int?

Does fire resistance protect you from environmental heat and does cold resistance protect you from environmental cold?

So far I haven't been able to find a proper answer to this, just people saying they should.
I know James Jacobs said they do at least twice (found here and here) but we all know his word isn't rule.