summoning Necrophim or Specters or Torturians outside of the Nightbane RPG ?

[Plane]

There's two forms of the spell "Summon and Control Astral Being" (or SACAB) where the 'minor' version can summon generic astral entities (minor or common... the semantics compared to the spell are confusing so I'd prefer to call minor entities 'lesser entities') while the major version can not only summon "greater" astral entities but also the 3 specific RCCs specified in the title.

This is from Between the Shadows page 127

Assuming this spell was learnable outside of Nightbane, how many of these creatures should be findable?

As best I understand, at least the Vampire Specter (if not also Necrophim) seems to be implied to be more of a Megaversal threat... so maybe them?

Torturians OTOH are explicitly humans who get twisted by the Nightlords so I'm not sure if random dimensions should be able to summon them...

A lot of this might depend on how the astral plane works... like I remember a non-canon Rifter suggesting there's 1 shared inner plane but each dimension (or maybe even planet?) has a different outer plane - could that explain how Torturians could be targeted w/ the spell from NBearth but not other earths?

This also seems like a consideration for the Summon Spirits circle (PF2p48) which explicitly targets both the Dreamstream and Astral planes...

I'm thinking if you actually knew Torturians existed (or maybe even a specific one) then sure you could summon them into PF but if you're just going "hey summon a random spirit" then it's going to prioritize generic things from your own dimension instead of unique types from others?

[Marcethus]

I would require the character in question to have the Lore: Astral. The availability of that skill depends on the setting. The way I run my games is One Inner plane and each setting has it's own Outer Plane. (Rifter 9 is the one that you're that you referring to. Though I had done my version of that before I had gotten ahold of Rifter 9)
Basic Astral Spirits would be available to all that learn the spell. Torturians would require a the character to be from or aware of the Nightbane Earth and it's associated realms. The Necrophim, I would require Lore: Astral with a penalty depending on how rare the GM wants them to be.