As a wedding and event planner, the only thing I can say is that you should be careful to not let others step on each others toes. I know for a fact that coordinating all those people will be hard, if you don't have a wedding planner. Its not to many. I've actually done a wedding where there were ten bridesmaids and groomsmen for each and still others in the wedding. So, you haven't reached the really high limit. Just lay down the ground rules and tell them if they're paying for their own things or if you are paying. Lay everything down in the beginining so there are NO problems come the day of.