Its vague, but the general consensus is Wutteat was found in space. I believe the books are more clear that Wutteat is the template that the Earwa inchoroi used to create the Wracu.
I wouldn't call it consensus - it's so far one person's head canon, which other people seemed to for some reason accept without further examination. I consider it just one of several possible scenarios. Wutteat can just as well be an advanced program of the Ark. Even more so, he refers to some unknown party as "his makers", which, considering all the Tekne aspects at play, goes more against the idea of his natural origins than for it.
I disagree completely, but we're reading the same stuff so there's nothing else to say for this one. IMO, complex social behaviors indicate an extraordinary level of intelligence, well beyond anything we see of the wracu - which are closer to bashrag/sranc though maybe a bit smarter.
Wracu seem rather fond of pathos, but otherwise pretty intelligent. Their communication reminds me of Aurang, only he just thinks about his genitals and all the things he would like to do with them, while Wracu prefer to vocalize their inner monologue - although with more focus on devouring (it's the size thing, I'd venture).
All this to say, Wracu very much fit into the standard Weapon Race role. They aren't exceptional, other than their physical variation. I see no significant reasons for why they should have special rules.
It's more that Bakker's comments seem to imply that - he outright states that Wracu have souls, that they have metaphysical interaction with Chorae, that their fire is neither sorcerous nor mundane, that they might be living topoi, etc.