my opinion (for what is worth)
i think DS played RP like a fiddle. most child predators are known master manipulators, they insinuate themselves into people's lifes with no problem in many cases.
i think he saw a stress, struggling woman with 3 kids, down on her luck and there was his opportunity.
i also think he payed her a lot of attention, maybe told her how pretty and young she was for having all those kids, enough to make her think that maybe what he was interested in was her, he also probably listened to her chatting about her problems with current live-in, no job, no money, etc, etc. she either saw him as an easy take (he would pay for her shopping) or truly believed he was a good samaritan
he groomed the mother to feel comfortable with him ,enough that she would let him take cherish to the fitting rooms and to allow her to go out to grab dinner with him.
yes, RP made it easier for him but of the two he had more experience conning people.
why i don't understand is why he acted out so quick? usually the grooming takes time before the attack occurs...also he did not make any attempts to disguise himself at all! some predators wait months even years before getting the child and the child's family defenses down...