Notes:
This is a bit of a digression which will become relevant a bit later.
It is possible and useful to make resources on the host and elsewhere look like basic Linux abstractions inside UML. hostfs does this by mapping host files onto files inside UML.
Another possibility is to disguise a SQL database as a filesystem and mount it as such in UML. This would allow queries to be made by doing filesystem operations such as ls and cd in that filesystem.
Other things may make sense as processes. Representing host services (like multprocess services) or machines as UML processes would allow them to be manipulated by process tools.
Using the existing file and process tools to manage outside resources may be somewhat non-optimal, but it would work. The interesting thing is that better tools could be constructed with small changes to existing GUI file and process management tools.