Is "Does your baby sleep sometimes" incorrect?
Not in my experience. Iam means sometimes. That it also means "ever" is not well discussed in the notes.
Well, it's mentioned at least... but I guess there could be more, if there's more to be said about it. Is there?
Not here, maybe at Lernu? I have 'speaking colloquially in Esperanto' & in there is a nice discussion on the issue.