As for Ambien and Lexapro- Lexapro can cause insomnia, so Ambien, a sleep aid, would not be a problem, chemically speaking. If Wilma had been sharing it with BamBam (lol} it wouldn't have posed a problem.
I find it interesting though, that KE moved on to chloral hydrate when Ambien did not work, as you mentioned. Like there were no other sleep aids that would work????? Glib, glib, glib is what I'm thinking.
It sounds, though, like Daniel may have been given drugs aka "medication" that were similar to the ones prescribed for him, as an aid, and out of ignorance. Which, IMO, makes methadone look even more suspect. It was not an aid. He was taking drugs for anxiety/depression. He was not a heroin addict. Why the methadone? It doesn't remotely fit with the profile of other drugs he was taking or his drug history. Compare, too, with ANS's ingestion of sedatives in response to methadone withdrawal.