We rented that appartement for your familly (2 adults + 3 childrens) : we managed to put one mattress from the living room on the floor in one of the two rooms to keep living room as dinning room only. We spent excellent holidays in Elba
The pictures give a very good feeling of that flat, except for the terrasses, but it was a good surpise when we arrived : they are on a 3 different levels basis, one of it being well protected from the sun for great outside lunch & breakfast.
two lovely beaches (sand & gravel) not as overcrowded as main beaches in Elba are indeed rather close by foot (5mn Zuccale and 15mn Barabarca and via pedestrian path) : that's wonderfull as in Elba, car parks close to beach are very tough to find)
The pool is big, with plenty of available seat around it, and enlighted by night.
Top location, we highly recommand it.