Clean Architecture, UseCases and Entities
Basically, you want to push your "instrumental" aware code as far as possible (on the circle).
Use cases are very close to the model and contain a lot of business logic - you want this layer very clean to be able to do quick and easy unit tests. So, this layer shouldn't know anything about storage.
But the fun part is when Room enters the room :) Room makes it so easy to have model-like objects that you can use around and IMO it's a grey area should you use Room annotated classes for your model or not.
If you think about Room objects as Data Layer objects, then you should map them to your business objects before reaching use cases. If you use Room as a built-in mapper of DAO to model objects, then IMO you can use them in your use cases, although clean purists probably would not agree on this.
My pragmatic advice would be - if your model has a complex structure built in from multiple entities then have a dedicated model class for it and map entities to it. If you have something like an Address, IMO just go with the Room entity.
Quite a lot questions within a single question. let me try to consolidate what I think I understood are ur key questions
Can Entities reference each other? the answer would be: YES. Also in Clean Architecture u can create a domain model where entities are interconnected
What should be returned from a UseCase? Answer: UseCases define input DTOs (Data transfer objects) and output DTOs which are most convenient for the use case. in his book uncle bob writes that entities should not be passed to use cases or returned from use cases
What is the role of the presenter then? Answer: ideally a presenter is converting data only. It converts data which is most convenient for one layer into data which is most convenient for the other layer.
hope this guidance helps u to answer ur detailed questions
More details and examples you can find in my recent posts: https://plainionist.github.io/Implementing-Clean-Architecture-UseCases/ and https://plainionist.github.io/Implementing-Clean-Architecture-Controller-Presenter/