Him, Manuwa and Glover. DC though has huge power in his hands (obviously), but basically just his hands (same with Glover). AJ & Manuwa have scored knockouts with more than just their heavy hands, Manuwa has stopped guys with kicks to the legs and guys with knees and punches. AJ has stopped guys with head kicks and punches. Manuwa is the most powerful overall and he has had even less fights than AJ in which he was able to prove that well-rounded power. AJ has more "KO"s scored on his record but again, he also has more fights. It also depends on the judges, some will score it a KO when it's actually a TKO or a TKO when it's actually a KO, there's a fine line at times unless the fighter is absolutely out cold.
In terms of overall power with all types of strikes, the answer is Manuwa.