Hi Hee,
Q1
If you mean the windows authentication, please refer to http://cutesoft.net/forums/thread/5888.aspx
Q2
CuteChat4_User is a part of CuteLiveSupport, it use to store the user info. SampleUsers just use for the demo of the CuteLiveSupport. If you will integrate with your own membership system, this table is not necessary.
Q3
No, for now have not the setting to remove it.
You can remove the text in the language file, then the operator will always shows the empty text there. But if the agent know how to set this too, he still can add the text again.
Regards,
Ken