How do I modify my CSVN UID?
The UID of the existing csvn user is modified during install or upgrade of CollabNet Subversion.
Does Subversion have a keyword that behaves like $Log$ in CVS?
No, there is no Subversion equivalent for the $Log$ keyword in CVS. If you want to retrieve a log for a specific file in Subversion, you can run svn log your-file-name or svn log url-to-your-file.