I'm speaking for the *Windows* version of MLO....
The answer to your question is NO, that custom views are NOT propagated to other files, in my experience. Then I found the Import/Export functionality for Views...
In MLO there is a feature to save and export Views. I thought I could use this to save views I created If you right-click on a view, and select "Export View(s)..." MLO lets you "save" a view, e.g., from my "Work" MLO file.
However, when I then used the corresponding "Import View(s)..." feature in my "Personal" MLO file, the views did indeed import, BUT with the issue that the *filter* settings for the views did NOT come across into the new file.
This makes the Import/Export of views essentially useless. So, I wind up having to recreate my custom Views in each separate MLO file.
If someone here knows how to export a view and save its filter settings so they get imported with the view, please share this info. (Or can confirm this is a known bug/issue)
James