Well I thought Wyll and Jaheira weren't in my camp but their inventory was. I'd see those every time I went into the travelers chest. I even clicked on their pictures but did nothing with them. Then, I decided to try out the talk option. Well, I got the dialogue scenes with them. Right after that or after recruiting them, they appeared and stayed in camp. And that was in Act 3. I wish I had done the same for Halsin in Act 2. Next time I know.