Have you already talked with Scar about Cove exploration? Not only witness Everette and Gunnar meeting at night, and you also need to finish the cove exploration. So, you can process to talk with Everette about Gunnar.
Have you "take a look" at the training ground? It seems you need to take a look there during daytime on Mon/Wed/Fri after you report Everette about Mythshore.
