You all start together, and end together. Don’t bring in new people partway through the project.
Set a halfway point for everyone on the team to gather and check the work you’ve all done.
Meet a day or two before the project will launch. Decide if any work needs to be cut to be ready for the launch.
Everyone finishes/launches the project together. No one has the right to miss a meeting or the launch and say, “Send me what you’ve done, and I might approve it, or not.”