Prosecutors said Beasley and Brogan used the job postings as bait in a robbery plot aimed at down-on-their-luck victims with few family ties that might highlight their disappearance.
The woman's father complained that police initially failed to react when he reported her disappearance, suggesting instead that she had gone off with someone.
Last week three lawmakers from Indonesia, Malaysia and the Philippines visited Vientiane and concluded that they were not satisfied with explanations they had received about the disappearance from officials.
She claimed the conversation about "babysitting" took place in April or May 2011, and that Mr Parker told her about it being Ms Spence in October that year, about a week before he was arrested in connection with her disappearance.
The BBC's Orla Guerin, in Pakistan, says that a week after Sahil's disappearance it remains unclear whether there has been contact with the kidnappers of if negotiations were taking place over a ransom payment.