OK on 1,2, 3,and 5.
On number 4 Yellow-throated Leaflove (Greenbul) seems to fit, however, the specimen is 14-15 cm and my references state that this species is "large" and around 21cm.
Data I have on this specimen is (verbatium):
Collected 2 Jan. 1906, Male, River Ja. S. Cameroons, Burnereo...