If your overhangs prevent most of the rain/snow, I would leave them off. The original design was just the louvers. We later decided that the HW cloth would further protect a weak point.
The coop is about 2' elevated. We don't clean under the coop. So far we have not had to rescue a chicken from under the coop or grab an egg. That could just be luck. Were I do redo the under, I would have hinged or removable sides. To allow easier access.
The gable end vents were...
We have the same coop. We located the attached to the front. It is functional and prevents rain and snow from getting in the open windows. We always leave the windows open as I think the design needs more ventilation. The whole back of our coop opens to allow for easy clean out. Which we do...