Customizing ADFS 2.0 login screen

We are in process of customizing ADFS 2.0 login screen and implementing SSO.

Q1. Can we rename the FormsSignIn.aspx to Login.aspx? If yes, what configuration we need to change, to tell ADFS 2.0 that Login.aspx is starting page or we just need to make the Login.aspx as the startup page and deploy it?
Q2. What is the Cookie name created by FormsSignIn.aspx, once the user is authenicated? Can we get this Cookie in other application (RP)?
Q3. In our application (RP) when user clicks on the Signout, we just clear all the application session created in RP? Do we need to redirect user to SignOut.aspx and How can we show the FormsSignIn.aspx back to user?
Q4. How can we know following types of cases from the below code of FormsSignIn.aspx.cs?
    1. User does not exist in Active Directory
    2. User credentials are incorrect
    
    try
    {
        SignIn( UsernameTextBox.Text, PasswordTextBox.Text );
    }
    catch ( AuthenticationFailedException ex )
    {
        HandleError(ex.Message);
    }
        
Environment
2008 Server (Not R2)
IIS 7.0
Active Directory
WIF
ADFS 2.0
.NET 3.5
.NET 4.0

Any help would really be appreciated.