Ah! Ignore the above. I suspect this is exactly why the Article class has the 'short title' attribute and the Folder class has the 'short name' class which are used first in the object name pattern.
The first part of your question regarding breaking links. If you change the name of an object then eZ publish will keep the old URL and forward this (using HTTP MOVED headers) so that e.g. google updates it's search index and users find the content, even after it has been removed.
The actual object name is what's deciding the URL alias, this can be configured in the class setup. As you mention the default article class already utilized this, as an option.
