I don't think a close connection to the cheerleading thing has to be made to have it be a good possibility that there is a connection, no matter how slight. You don't have to attend the practices to chat with another parent in the parking lot, drop kids off at another cheerleader's home and meet a parent in passing, or to invite someone for a sleepover or ask for ride, etc. It's a small town. The kids chat about each other and parents usually hear all about the other kids while driving them places, at least I did when hauling my kids around.
If she was targeted, and I think she was, it would be very likely that her face and name were familiar from the real estate marketing and he picture being on advertising, the internet, possibly signs around town. Her son even said this in an early interview. Then from there, it wouldn't be a stretch to recognize her in any brief encounter at the cheerleading clinic.
Even if her jewelery and bling was mostly costume, I am not sure AL would assume or realize that. I don't give him much credit in the smart department. BC drove an expensive vehicle, had vanity plates, was attractive and perhaps dressed flamboyantly and in his world of selfies and self promotion it all added up to her being "rich".
I haven't figured out the motive, but I think that the referral came from a "hey, a buddy gave me your name (or someone at cheer clinic) and I am in the market for a cash sale for an investment, or blah-blah...my wife and I would like to see some property..blah, blah", kind of referral and not another realtor. Her husband said she was excited because it was a cash deal and I think most realtors would be saving that kind of sale for themselves and not referring it to another agent.
Do we know if all of the homes (I believe it was 3) scheduled to be shown were vacant? An owner occupied home would not fit into their scenario, I don't believe. I think that the home they went to was by their request and not at BC's suggestion.