These 12 are not all the narco gangs in New London. But they are a sizeable portion of them. They are good enough for him to start with.
In fact, he didn't expect this much. It is clear that Red Dream had done a good job. If he wants more, he can slowly increase the size of his cabal in the future.
While he was thinking of the future, all 12 of them stood up to welcome him. They were saying their greetings, but he wasn't paying attention to what they were saying. Instead he focused on each of them to determine their threat level.
Unfortunately, he didn't see anything special. They were all harmless to him. But this only made him more confused.
He expected to see at least one thing out of place. Seeing nothing doesn't mean that there is no danger. It only means that there is no danger to him currently. There could be something dangerous in the future.