This is a somewhat good news, somewhat bad news situation.
First the somewhat bad news:
To the best of my knowledge you will not get the 'near real time' behaviour you seek. EA can recognize and warn you, depending on various settings, that the background model has changed. However, (at least some) things that are happening in an open session of EA will not be updated in real time.
In particular, diagrams that are open on your desktop will not automatically update themselves. [I keep thinking there's a setting for this but cannot remember what it was; it was probably only a dream.] You can reload an individual diagram - just right click on the diagram tab (usually at the bottom of my screen, but configurable) and select the appropriate context menu entry. There does not seem to be an easy way to do this from the main menu. [Again, I may be missing something here, but I never seem to find it anywhere other than the context menu.]
Another area where you may experience problems is the project view tree. I have found that removing and replacing a package and its internal structure - which you might do with a working copy, or an internal reference model - can cause a 'phantom' entry in the tree. You might have two "Working" packages side by side, one is the 'real' one, and the other is the one you deleted. The tree will not update itself unless and until you reload the project.
Now the somewhat good news:
You can call Repository.ReloadDiagram(DiagramID) from the automation interface, this will clean things up in the instance of EA you are connected to. This works fine for an add-in, but does not solve the problem if you have EA open on your desktop and a concurrent connection to a (shared) model from an external automation client.
You can call Repository.RefreshModelView(PackageID) to refresh a package hierarchy in the tree (and perhaps more). This can also be called with a PackageID of 0, which will refresh the entire model.
You can call Project.ReloadProject() to reload the entire project. [Remember, you can obtain a refernce to the project interface via Repository.GetProjectInterface()] Once again, this affects only the instance of EA you are connected to via automation. If you have another session going from the desktop that session will continue to experience double vision until you manually reload.
Please let me know how you make out with this.
HTH,
David