I stayed in a monastery guest house in Venice. It had a curfew- that didn't bother me as I had no intention of wandering the Venice streets after midnight. The entrance door would be buzzed open by a worker or nun. The room was clean and plain - think college dorm room. The room key had to be left at the reception window when I left each morning for a day of sight seeing. It was located on a side canal - quiet location. There were no religious symbols in the room.
The place I stayed at did not include breakfast. It had a kitchen with fridge, dishes and cooking tools. I bought items for my breakfast and had to label them with my name and room number.
The bed was okay- don't expect a plush mattress like you would find in a 4 or 5 star hotel.
Edited to add- it had AC and windows that could be opened, but no screens.