Welcome to the forum
What I could see working for you is having a master project for each channel and depending on the complexity of the pieces of contents either work with projects that are multi-homed and/or linked to the master projects, or have a task with subtasks for the pieces of contents. You can choose the privacy settings for each project and only share tasks and projects with people you choose.
May I ask you which Asana subscription you use and if you have been working with our solution much at this stage? We have loads of resources out there to get started with Asana. Have you checked this guide article yet? It provides you with use case examples, but also video resources on the right hand side. If you haven’t checked those resources yet, I think they could be super helpful to you to get some ideas about how to build workflows in Asana.
And you are already one step ahead by having joined this forum There is a Use Case category with a lot of input and ideas. Also, please keep asking questions here and share what you have built so far with us - this community is very happy to help you out
Looking forward to hearing more from you.