hmm, it will require a lot of template modifications to get rid of the userid's, because every reference is done via them.
you can avoid some (for example the getinfo also works with a username) but for example to search for all posts of a specific user, you have to hack a lot of files, in deep, so i suggest not to do so.
as for postcounts, that's jsut an easy conditional template edit, you may find out more on vbtemplates.com