Such great ideas @ABp! My key recommendation when anyone is thinking through building a system is to map out what the workflow of the average person using it would be. It can be really easy to get caught up in all the possible connections, but the most important part of any system is the human element and making it super clear and easy.
If the workflow will be giving people one place where they can see everything that’s going on, I would recommend having a doc with several cross doc’d tables of their tasks across areas filtered by the =User(). They could then jump off to the docs of choice to dig deeper or take action. You could also include a section with the company wide tasks filtered by week or month across all docs.
For your question about planning work ahead, I really like @John_Coda’s template for roadmap and utilization - https://coda.io/t/Product-Roadmap_txK9SyEKNLt
It might get some good ideas flowing!