I'm too new to trikes to comment with any authority, but the stories I've heard experienced trike pilots tell about flights into IMC range from "no big deal" (the most common response), to scared for their lives.
An AI, of course, would be of little use on a WSC. Very few trikes are even equipped with them unless they have Enigma or other EFIS systems that incorporate that functionality. But on the other hand, trikes are inherently stable because of their design. There's also direct feedback from the wing because the pilot is directly moving it, rather than moving control surfaces which in turn move the wing.
Like I said, I'm much too new to that world to speak with authority, and I don't think I feel like flying into IMC to report what it's like. But I think if a trike pilot has any advantage in this regard (other than the inherent stability of the design), it would be the direct feedback provided by the control bar. In an airplane, if you're in an unusual attitude with neither visual reference nor AI, it would be a lot less obvious than in a trike, where the attitude of the pod with respect to the wing is both directly controlled and can be determined by the position of the control bar.
Helicopters flap up on the advancing blade and down on the retreating blade. Birds wings are both advancing airfoils so they can be flapped up and down together.