> - If I am on a branch where this issue exists and unaddressed, is it easy to find out if there is another branch where this issue has been addressed
I do not have a solution for that.
> - I am on a branch that does not have the issue reported, but know it's reported on another branch -- does that mean the issue doesn't exist on this branch?
The idea was to create issues only on on a separate branch which is constantly merged into master. Then all branches downstream of master will get the issue when they rebase/pull.
Scenarios:
1. You're on branch `x/y/z`, you notice something that should be added to the issue tracker, you stash, switch to `/issues`, add the issue, push, switch back to `x/y/z` and pop.
2. An issue is to be created, the creator clones `/issues`, creates the issue, and pushes.
This way, all issues are on all branches, but only the branch dealing with an issue will update it.