Yes, so technically the roll for a level 8 Ranger would possibly be d20 + 28, which is 12 for the stack bonuses, 8 for ranks, 5 for wisdom bonus, and 3 for the automatic bonus for a class skill with ranks in it.
The wording is there correctly.
Cauldron becomes the pre-requisite for Brew Potion as a witch. Therefore at level 1 you have Brew Potion as a bonus feat.