About Kenny and the Wagners, as you can see from this map, KR was only a few miles down the road from the Wagner's Flying W Farm.
https://expo.advance.net/img/3230a5366b/width960/faf_map2.jpeg
I'm sure Kenny and the Wagner's knew each other very well and it would be easy for the Wagner's to go stop by Kenny's camper and give Brownie treats and have Brownie get comfortable with at least one Wagner.
Over those months of planning they were "cultivating" the dogs to be familiar with them. According to the indictment they studied the Rhoden's surveillance methods including the dogs.
I don't think Kenny let anyone in at 3:00am in the morning, if he had he would have been shot out of his bunk not in it. The Wagner's either knew how to get in and planned it out, or Kenny left the camper unlocked for one of them for some reason.
Despite custody, the Wagner's could still act friendly towards Kenny and Kenny would not be thinking he was in danger. Kenny was killed perhaps in part to look like a Cartel hit and in part because he would want revenge and might suspect the Wagner's and take matters into his own hands.
They did not pick their victims based on who knew about the custody fight. It's been written in MSM articles that friends and family and even their pastor said the custody situation was contentious. LM mentioned it right from the beginning.
The Wagners shot the people they wanted to shoot and if they wanted KR2 out of the picture she would be the 9th victim. The Rhodens were under heavy surveillance, I think the Wagners had their houses bugged and knew that KR2 was not spending the night.
And I think KR2 stayed friendly with the Wagner's because of Sophia. She had no choice if she wanted to be in Sophia's life and even be her godmother.
Also, don't underestimate Jake's inside knowledge of the Rhoden's movements. Problems or not, he would still be interacting with them because of Sophia and he could text Hanna at any time under the pretext of "parenting" when in actuality he is fishing for information, along with all the other surveillance.
I think they planned very carefully to pick just the "right" night when the 8 were home "alone". If the Wagner's were just going to randomly kill whoever just happened to be sleeping over, then the murders were not as sophisticated and meticulously planned as LE makes them out to be. DeWine and Reader feel they targeted those particular 8 victims......My 2 Cents........