Based on the skills that everyone has. I believe the best people to add to the team would be Tim and Maria.
I initially picked Tim because he would be best to lead one the workshop classes as well as come up with the curricula needed for the workshops. He seems well energized and passionate about the sciences enough to be willing and capable to work with the people attending the workshops. He could make sure that the curriculum is entertaining and creative to keep the attendees interested.
As far as the behind the scenes goes with reserving the room, advertising for the workshop and finding the funding from local sponsors. I believe someone who could greatly contribute and help would be Maria. Maria is very organized and well thought out, I believe we would all be able to split the work evenly. Due to her enjoying working behind the scenes I feel I would be alongside Tim in helping to lead the workshops as long as we all worked on a thorough and detailed material is laid out. I believe the 3 of us would work well together as a collective unit whereas the other two i wouldn’t think there would be a solid group foundation to work with.