Pro tip: It's mega-important to talk about tensions as soon as possible, before they get insurmountable. And about role definitions and competencies.
Indeed. Defined roles help to establish what, when and where things must get done and who's taking care of this. The only issue that rises from this is that, in a small team, members must be "agile", ie, be able to wear more than one hat. I don't know what kind of system you guys are using, but one thing that's really helpful as a producer is to make a list of all the tasks at hand to reach the current milestone on little post-it papers. You place them on a board with the names of each member. By doing a meeting with the members and assigning the tasks by placing the post-its next to the names, not only can you easily see the workload of each member and everyone knows what the others are up to. If some of your guys are online, a webpage or an online google doc/ excel sheet can do the job as well.
Good luck with the project!