This is a little difficult question to answer, ideally you should pick the best at the department roles that way everyone knows their role and try to focus on the goal project, but I think that would be only in a perfect word, and this is not a perfect world so, we have to account the personality of people that is going to be in our project team. I have experience a lot of working with different type of people and well it is difficult working with some and easier to work with some others. to answer your question, I believe I will prefer to go with people that I can get alone even if they not the best at the department role, we as you said this is a project team, so we all should be helping each other to achieve that goal.