Now before the team starts ramping up you need to get it clear what the project is aiming for. You've done the vision and you know your stakeholders which is great. But you don't really know what the project is.
This is where your service architecture comes in. The purpose at this stage is normally just to do the Level 0 which will define the different groupings and areas for the project. For mine we've got 3 top level services which define the different areas of the project. They've got different purposes and focus which means the different groups will have different focuses and structure.
You want to get this done before your team starts forming into cliques as you want them to form into cliques that match the business structure of your project. Sketch out the services and then make sure you set up the teams along those lines. This makes sure that as you move forwards in the project you have the clarity required in the team to deliver in the way that you want.