It is interesting. If Rahel is involved, she knew about the mascles from near the beginning, before any deaths but Sir Felkar. Using my hypotosis, there was some reason for Sir Ewen's tag to be used. Now I can't see this as an effort to draw out Sir Peten, she could have done away with him (I believe) with little trouble (Koltho to boot). Anybody have an idea why anyone (especially Rahel) would want to put at least three extra murders on Sir Ewen's plate (Baron, journeyman, Prophet)?
It is also surprising that (as I think I have mentioned before) Lord Graver did not see fit to let Bevan into the news that Ewen was more than he claimed to be (deryni). If he did, she did not choose to share it with anyone else. Since she is, using his words, one of his best agents, why could he leave this important piece of a puzzle out?
Not knowing the capabilities of deryni, we only have the words spoken by Ableron for Bevans' benefit. If added communication is able to take place, we don't know it. Anything which happened with Lord Graver will have to be explained (not how, what).