I wonder if the new Trust NPCs are limited time or permanent.
If I'm understanding your question correctly they are permanent.
Prishe will be available by examining the Walnut Door (K-7) in Tavnazian Safehold after completing "The Chains Fall Free" (btw, I don't think there's an actual mission named this - so I'm assuming it's 8-4).
Ulmia will be available by examining the Dilapidated Gate in Misareaux Coast (I-11) after completing
Dawn.
Iron Eater will be available by speaking to him in Metalworks (J-8) after having access to Naji, Ayame and Voker.
Gadalar will be available by speaking to Fari-Wari in Aht Urhgan Whitegate (K-12) after completing
Embers of His Past.
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