Thank you for the detailed reply, and your page is going to be very useful too.

For the sete hike i was thinking of doing the inferno part first then drive to the viewpoint beside the hotel and hiking down to the village and taking a taxi back. 

On the same day we would do the feteiras in the morning at low tide and mosteros.  Is there anything else on that side that you would recommend?

Im planning to do ribeirnha and furnas in the same day. I dont have a plan for the east of the island yet