Had to do more reading, and yeah, the familiar would be available as a spiritualist. It's just the summoner's pet/ally and summoned shadows they refuse to stick around with. At least, not if it's the spiritualist that summoned said endolen or shadow. A familiar though is fine. And a Figment fox familiar would fit so well. That wouldn't come online till level 3 though, so further splintering of the psyche. Some of the reading was finding out exactly what skills/feats would be needed to set up for eldritch heritage.
Obviously, I'm planning to do Bill as a rather fractured madman. Yes, pun was intended. A (maybe) justified paranoia about shadows and the dark, obsessive need to be in bright light to fully relax, and when scared a broken speech pattern.
But the majority of Bill's fear response became the phantom known as Will. Who constantly tells Bill about what terrors are coming for him from the shadows (accurately or not). So maybe such behavior is normal? With the fox familiar eventually being formed by his inquisitiveness, of course.
Okay, so the idea of a lovecraft mythos style game combined with the Paranoid drawback to truly inspire me. And as I mentioned, the fractured soul archtype seems tailor made for such a game. Probably because it was.
Dang it, I like both concepts. How about I go with Bill. But if something permanent like unrecoverable death occurs I bring in Tympest?