Here are links to some of the books used in the campaign. You need not purchase them, although it is recommended that you familiarize yourself with sections that affect your character. The DM will provide these books at the gaming sessions, if needed. It is a good idea to have the pdf versions of the core rulebooks on your laptop that you bring to the games.
Please note: There may be spoilers. Also, I am not using all the rules from all these books. But if you were interested, here they are.
Regarding availability of feats/items/spells – Anything found in the Pathfinder Core Rulebook is available for characters. If the item in question lies within in ancillary supplement, such as the Advanced Players Guide or Ultimate Combat, usually DM permission is required. I am not too picky on it, but please respect that I may not be familiar with the items in question. If I feel they are over powerful, I may veto them AT ANYTIME. This applies to certain items in the Core Rules as well. If the rule in question comes from a Pathfinder Society Scenario or other tertiary supplement, the item in question may not exist, or may be very rare and difficult to obtain. Thanks for respecting me on this.