My prediction is there will be multiple attempts by multiple attackers; and one of those attackers, or their sponsor, will escape detection and retribution. So, it's possible that Harry will track down the final would-be assassin only to find that someone else killed them first, thus shielding their employer from identification.
You see, there are two possible reasons why someone from the White Council would target Harry. First, a few members of the Senior Council; in their typically arrogant and self-righteous manner, might determine that Harry is a threat that needs to be removed. I think they would fear what Lara Raith could get a compliant Harry Dresden to do for her and the White Court. The second reason is that Peabody's unknown partner in the White Council; maybe I should refer to this individual as Wizard X, wants to carry on the mission of weakening the White Court and, if possible, set the White Council and White Court against each other. The alliance between Winter and the White Court is something Wizard X would want to stop. Killing Harry and making it look like the Council was responsible could potentially accomplish both goals.
About the Genoska; Genoskwa? whatever, I really don't care. I don't know why Jim decided to bring this one shot goon villain back from the dead. I hope the big guy makes an attempt so Harry can get rid of him for good, though I suspect we might not see him again until we see Nicodemus again; so not for some time. Plus, there is probably some special way that Harry will have to use to kill the big ape for good.
I think there will be three factions or individuals who try to kill Harry. At least one of them will be; if not generic, at least predictable. I could see a pack of ghouls from the LaChaise clan make an attempt.