Thing is, from the wording of the Affidavit, BB isn't vague on claiming relationships with randoms. He straight up named KC and CW. Doesn't appear he was wrong in CW's case.
Information of this nature would be acted upon immediately by LE. For that reason itself, I can't imagine BB throwing KC's name around for the hell of it. I don't really think we need any more confirmation than that.
What is strange, is the conflicting stories about the C's presence that day. I can't remember if it was here or a FB group that someone related to MC claimed she was the one who called BB that morning. Locals on here have heard similar. Suggests she was there at least, if true.