Despite Jon's paranoia, the Riley's arrival had nothing to do with his errant wish. Sam had gotten a promotion from his company, where he worked as a senior accountant, that came with a transfer to their Lakeview branch. They'd actually been around the old Russo place before, when they were viewing the house, but Jon just hadn't noticed. Indeed, even the uncomfortable feeling he got when he met Stacy's gaze was of his own imagination; he was so keyed up and anxiously looking for what the wish had done, that he was projecting those fears onto the perfectly normal new neighbors.
That said, he had made the errant wish, and while the Riley's weren't the result of the wish, they were to be among its targets. Later that day the wish would finally take effect, making changes in both the Gibson and Riley households.