At the moment, I'm taking a very conservative approach to adding what I would call "file manager" features. I'm not trying to create a Finder replacement and with the restrictions that the app sandbox imposes, it's very difficult (if not impossible) to even perform some operations that users might expect if they started to see Fileloupe as a file manager. That's not to say that I'm against them ("Move to Trash" might appear in v1.1) but I am being overly cautious.
With specific regards to Finder labeling and tagging, it's more likely that I'd add support for Fileloupe to be able to show labels and tags long before I added the ability to add or edit those tags.