I'm convinced she was well aware. Certain details had to come from someone with intimate knowledge of the neighborhood, among many other glaring red flags ...
I also think she was aware, but on this specific point -- it's possible her family members (mom/parents/brother) had been to their home in Tally enough to have knowledge of the neighborhood or that he drops the kids off in the morning, that kind of thing, without having to include WA necessarily.
Rough spectrum of WA's possible involvement in the plot:
1) she initiated or co-initiated the plan with family members
2) she was not involved initially but became aware of the plan at some point BEFORE the murder
3) she was not involved initially but became aware of her family's involvement at some point AFTER the murder
4) she never knew anything about it .... and was shocked to see her brother's name associated with alleged hitman today
There could of course be other shades between/around those four. But to me, 4) almost defies belief .... as someone mentioned above, when the hit actually happened she would have at the least had to be suspicious of her family, since it made her/their "problem" go away, would start asking her own questions. Plus law enforcement questioning would have likely gone down this road with her and the family. From all indications she was extremely tight with her family (lived with her parents after initially moving back to south FL, right?). At a minimum, if her brother and/or mom were at the controls, I think WA would have been told "something bad might happen to Dan soon .... don't ask questions, you know nothing" or the like.
On my scale above I lean towards 2), with 1) and 3) also possibilities.