Replication depth 0 hides also it's own contact

I continue the discussion from GitHub:

@gareth how can one limit the editing of peer persons (at the same hierarchy level) using the access restriction?
The only way I would see is to set the replication depth to 0 for this particular user role to 0.
But then, the user cannot see his own person and as a consequence, cannot start app forms, because they are tied to a person and not a user.
The person information then cannot be loaded into the form and one gets an error.

How can I use the replication depth to prevent users editing persons at the same hierarchy level?

Is it possible to include an additional level in the hierarchy to contain just the documents that the CHW should be able to access? Essentially this would mean each CHW would have their own “CHW Area” with all their households allocated to their area.