Regarding nest areas, two is fine. If you had five you will find that they will all end up using the same nest box anyway. I think you will find that you can not think of a question regarding chickens that has not been asked on this site at least ten times. The search box will lead you to a...
I think that the coop you are thinking about will be quite sufficient for 5 chickens. I also think that it is important for them to have a sufficient run and the size of the run will be more important then the size of the coop. In my experience I have found that the chickens only go into the...