Your highest rank is based on your level. Technically this would give you a single rank four slot at level 9, a rank 5 slot at level 11, etc. without taking the expert or master spellcasting feats.
Yes, if you had spells from your sorcerer that overlapped with the mystery’s spells, you could cast them using the extra slot without taking the basic spellcasting feat.
True. That was probably a bad example. But if you picked up basic oracle spellcasting, that would let you cast the spells granted by your mystery.
So you’d get an extra slot at your highest rank. For basic spell casting, this would be one rank 3 slot at level 8, so with gift of power you’d have two slots, one that would only let you cast spells granted by your mystery.
The first part of the feat gives you an extra spell slot of your highest spell rank, but that slot can only be used to cast spells granted from your mystery. For an Oracle dedication, you’d need to take additional archetype feats to get access to Oracle mystery spells, e.g., https://2e.aonprd.com/Feats.aspx?ID=6220
If you also happen to pick up divine access or mysterious repertoire, then you can use this extra slot to cast spells granted by those feats as well.
https://2e.aonprd.com/Feats.aspx?ID=6064
From reading this, it doesn’t look like it would affect your other spells at all:
Your mystery grants you additional magic. You have an extra spell slot of your highest rank, which you can use only to cast one of your mystery's granted spells, heightened to this rank.
Special If you have the divine access class feature or Mysterious Repertoire feat, you can cast spells that you learned from those abilities using the additional spell slot from Gifted Power.
I’d highly recommend joining the Foundry discord if you haven’t already. It’s very active, has channels for anything and everything, and people are generally helpful.
Their GitHub page might also help with technical details.
My understanding is that for initiative, the Stealth roll doesn’t remain secret. This is the scenario I always envision:
PC goes ahead of the party to scout out a room or other location. They roll a secret stealth check before they move to avoid notice. If that stealth check beats all the Perception DCs of the NPCs, he’s able to scout successfully, being unnoticed by the NPCs. However, if that roll doesn’t beat the Perception DC of at least one NPC, I will cal for an initiative roll, using the secret stealth check as their initiative, thus revealing how well or poorly they rolled and letting them know that something has given them away.
The normal rules apply at this point. Anyone who’s perception DC is higher than the PCs initiative would treat them as undetected - meaning they’ve noticed something (a moving shadow, a small non-localized sound, etc.) and will act suspiciously, possibly moving towards what they noticed to investigate. Anyone whose perception DC is equal to or below the initiative roll would continue to treat them unnoticed.
If you’re planning on GMing, you’ll definitely want the GM Core, which is the remastered content. When Paizo did the remaster, they split the CRB into GM Core and Player Core, though they reorganised some of the classes. So Player Core is a blend of the CRB and the APG and Player Core 2 covers the rest.
Also, all of the rules and pretty much anything that isn’t specifically lore or settings is available on Archives of Nethys.
I backed it and super stoked for it to come out. Huge fan of the PF2E system and really hope they implement a faithful adaptation of the rules.
Ya, that’s a bit unfortunate, but not surprising - Paizo want people paying full price for the remastered content right now.
I’ve purchased Abomination Vaults, Age of Ashes, and Outlaws of Alkenstar, but have only played AV so far. The Foundry modules are worth the money alone as they make GMing that much easier. There’s a fair bit of overlap between the bundles, especially at the lower tiers (which is by design), but it’s still an incredible deal.
Not clear if this is using the ORC license or a specific licensing agreement with Paizo. My guess would be the latter. No idea if it’s related to 1E The Dragon’s Demand adventure.
Age of Ashes would be an option if you want dragons. It’s one of the older APs, but it’s a full 1-20 campaign. I haven’t run it yet, but from what I’ve read it needs a bit of work by the GM, particularly around tuning encounters as there are several that are overtuned. Fortunately there are lots of community resources to supplement/augment it.