I have a feeling the way the murder was conducted is connected to the motive. The crime seemed very...calculated and quick. The clear sign of someone who wanted to get the job done and didn't care for anything fancy.

Honestly, the chair against the door is odd: the doors automatically lock and given the state of the crime it's likely Lydia was already dead by the time Felicia Marlow attempted to enter the bathroom. If Felicia didn't feel the need to forcibly enter the bathroom, then we would have gone for a while without finding Lydia and it doesn't take more than a couple minutes to drown a person. If the criminal was trying to make it look like a suicide, then the job is sloppy. I honestly don't believe motive plays any large role into this - this was a murder done for the sake of committing a murder, from my perspective.

As for the memories...well, I think the suspects should mention if they feel as though there are any blanks in their minds. If one of the listed suspects is absolutely the culprit, then there's no need for everyone else but them to speak on it.

[Honestly, Susan and Felicia are the two people Alice least suspects of the five.]