The hitmen had to wait until after 2:53, so that they would be killing Cooper and not Dougie. We know Bob Cooper knew what day the lodge would try to pull him back in, so it makes sense for him to hire the hitmen to kill Cooper since he knows he is coming.
Plus, like I mentioned above, I think it fits with Jefferies wanting Ray and Darya to kill Bob Cooper, but only after Agent Cooper has returned. I think it has something to do with the way both of them now seem mentally impaired. Like they are splitting their intelligence, or people arent meant to exist alongside their dopplegangers outside the lodge.
Jefferies is going to turn out to be scheming against the evil coop. Remember, in Fire Walk With Me he says "You think you know who this is here?" or similar, referring to Dale Cooper. The timeline is off but this is Lynch we are talking about