Hilton Ottawa Airport
There are no couches at YOW, so the Hilton it is. (YOW is NOT an overnight airport) I would give the Hilton a call and determine when the shuttle begins - or - is it all night?
Who is the carrier to Varadero? I know the MLL lounge opens at 04:30 but their first flight is at 06:00 am so it must be a charter?