To be fair, Kayla has been unknowingly groomed for most of her life for this exact thing and has been walking for days specifically to get to Isabella, so the likelihood is pretty high on her part. Ezikariel came with Isabella, so she gets a pass too. So does Isabella, since she needs to be somewhere. So it seems to be just Selena and Orlith that might be unlikely. And Selena seems to have a goblin thing for anyone who might be able to breed her?