Clover Heart's Suite Medley

Five varieties of the same music I quickly edited together. Each song has more instruments than the previous one. Can you guess which instruments get added throughout the medley?

§1: 0:00
§2: 1:54
§3: 3:47
§4: 5:39
Clover: 7:30

DL: http://www.mediafire.com/?2v77eb1hz79gaob