Correct, players will be paid an appearance fee by their national FA for international games. England players donate that fee to charity, I believe a lot of the players of bigger nations also do this.
I believe clubs are only compensated if a player misses training for more than 28 days when...
There is the potential for Mitoma (and others who go to the AFCON) to miss 4 Premier League games, possibly 2 FA Cup matches depending on when countries want players to be realised as I expect they’ll want players released before the third round games which are scheduled for Jan 6th.
Then...
The AFCON is also being played at the same time as the Asian Cup. Starts 13th Jan with the final 11th Feb. So that's Lamptey, Baleba and Adingra who could be unavailable at the same time Mitoma is.