I do agree with all these points, each would play a critical role in project success as it all depends on each other in a way or another. For me, I would add another two important aspects that would affect the project flow and its success:
1. Proper risk management policies: “Risks Happens” and without a clear guideline and plan for managing risk throughout the project, different unpredictable issues could occur at any point of the process and would affect negatively the project timeline, performance or budget. This would certainly, if not handled correctly, lead to project failure.
2. Proper project planning: planning a project is defined at PMI website: “deciding in advance what, when, how, and who will take the necessary actions to accomplish established objectives”. This means that any failure in planning would prevent executing strategic project goals. An example could be not planning for any sudden leave of a team member.