Just got an answer from Damon.
My original question I sent:
"1. If Strange Delusions causes a card to gain a faction affiliation, is that in addition to its printed faction affiliation? If so, then we need to know how to answer questions about whether a card belongs to, doesn't belong to, or is the same/different faction as another card. There are many cards that this could affect. Is a multi-faction card from a different faction than a card that shares only one of its factions for instance? Two multi-faction cards that share one faction? Maybe that faction is Neutral?
2. How are Neutral cards treated? The rule s say that a Neutral card does not belong to any faction. But we're not sure how this fits with some cards. Is a Neutral card "a different faction" from another card? (example: Communal Shower or Professor Lake) Does it matter if the other card is also Neutral? What if the Neutral card has another granted faction from Strange Delusions?
3. Is a Neutral card from the same or different faction than another Neutral card?
What we're looking for is a consistent way to answer all faction related questions about Neutral cards, and also all faction related questions about multi-faction cards (one of which might be Neutral) - provided that you rule that multi-faction cards exist from Strange Delusions.?"
And then the reply:
"Neutrals, as the rule you quoted says, do not belong to any faction. That solves all the questions you asked regarding neutral cards. You cannot compare something that does not exist to something else. Neutral cards have no faction so they have nothing to compare, in the case of Communal Shower that means you can commit a Cthulhu character and a Neutral character both to the same story, no problem. A Neutral card does not belong to the same faction as another Neutral card, because they belong to no faction at all.
Strange Delusions will give a character an affiliation of your choice but it does not say anything about removing existing affiliations, just adding one. So a card that was Cthulhu, could be Cthulhu Hastur. It would match both factions and treated at all times as if it were both factions until Strange Delusions effect ended with the phase it was triggered. If a card said Cthulhu cards cannot commit to a story, that card could not commit. If a card said non-Hastur cards do not count their skill, it would count its skill because it is a Hastur card. Communal Shower would prevent it from committing to any story at all since it is a character from different factions."
Magnus, this mainly differs from your post in that Damon is saying that a 2-faction character is (in effect) a different faction FROM HIMSELF.