I think Zedd being disappointed in Taralynn came up in discussions we had when I was writing The Bond Of Family and so it's headcanon for me now.

Zedd/Shota offspring - plot bunny? :D

Yes, it might not always be true. However the placebo effect is incredibly powerful - and the better the 'trappings' the more powerful the effect; an injection of saline works better than a sugar pill for example. So believing you've been enchanted by a Wizard of the First Order would be one hell of a placebo :D