Bolasie is Everton's fourth major signing of the summer.
Medeama beat TP Mazembe as holders Etoile du Sahel advance.
Bolasie has scored nine goals in 89 Premier League games.
Sunderland sign defender Papy Djilobodji from Chelsea.
Gernot Rohr previously coached Gabon, Niger and Burkina Faso.
Andre Ayew scored 12 goals in 34 games for Swansea in 2015-16.
Ogenyi Onazi joins Trabzonspor from Lazio 'to clear my head'.
Ghana midfielder Kevin-Prince Boateng joins Las Palmas.
Jorge Costa had been in charge of Gabon since 2014.
Chelsea winger Mohamed Salah signs for Roma on permanent deal.
Round of 32
Match 80
Day 21
England vs Congo DR 2:1
Goals England
H. Kane (75', 86')
Assist England
A. Gordon (75')
Goal Congo DR
B. Cipenga (7')
Assist Congo DR
C. Mbemba (7')
Congo DR
England