I think in addition to i think him was also been friendly and familiar with the teams just as you have made mentioned the coach had long time know the player staffers, and other teams, pulse i think the coach has established relationships with the player.
What really killed the Super Eagles recent matches were the coach fault because he selected those players so we should not blame others and the next persons to blame are the players. They would have using this opportunity to do well so they can be used in other games and like this I don't think those players can be used in any other international games but in local games.
The coach was not having much experience on the players and that is why the technical crew is with him to direct and select the players because they know who is who.