This is true. I've thought about those possibilities myself.
The problem I have with this personally is: Over the years, I have bought GS cookies from just about evry kid who has come to the door. That would be several hundred times. Sometimes they had their mothers with them, sometimes they were in pairs or threes, and sometime they were by themselves.
The number of times that I've invited anyone inside?
None.
To me, the fact that DW invited them inside indicates that he was either: a) an unusally friendly or very lonely person; or b) had an interest in either Brenda or Danielle.
In my thinking, none of those explanations works well for DW. He should never have invited them inside the house. Brenda, maybe, but only if she was by herself and if he liked her.
TOH, the reason DW invited Brenda and Danielle into his home was given in the PH and Trial in testimony. To wit:
Westerfield was in the middle of refurnishing his kitchen. The Kitchen area was draped in plastic.
Brenda said that she noticed DW was redoing his kitchen, and that she was interested in redoing her own, specifically the drawer/cabinet knobs. SHE ASKED Westerfield if she COULD COME IN AND SEE THE KITCHEN.
He took her on a tour of the kitchen, and while talking with her, HE SAID that Danielle and her brother ran ALL OVER THE HOUSE, UPSTAIRS, DOWNSTAIRS, the GARAGE, the LAUNDRY AREA. Then, Brenda said, the kids came to her and asked if they could go out to the POOL. DW said YES.
This was DW's statement to police BEFORE he knew he was a suspect.
Brenda's statement AFTER DW was a suspect, after the PR team worked with her, After her close personal friend (a retired policewoman) advised her in police investigative techniques and police interviews, (and BTW that friend was a 'friend' of the investigators), BRENDA said that the KIDS NEVER LEFT HER SIDE. EVEN THOUGH THEY HAD TO COME TO HER TO ASK TO GO OUTSIDE, they never left her side.
Hope that explains "WHY" Brenda, Danielle, and Dyllon went inside DW's house on a GS cookie sale.