Force All Guests to a Custom Login

[firebrand media]

I see this question asked many times for vBulletin4.x, but I can't find clear answers.
We're building a site that is a totally closed community. All guests must login through a page with ONLY the login fields.
The login page cannot display the regular site navigation.

It's OK if the error handling goes to the regular login, but it would be preferred if we could do that on a screen without the navigation as well.

So I need three things:
1) How to force all guests to the custom login screen.
I tried this into global_start:

if ($vbulletin->userinfo['usergroupid'] == 1)
{
$templater = vB_Template::create('my_custom_login');
print_output( $templater->render());
}

It shows my custom login template to guests, but logged in users don't get stylesheets.
I also tried a version that does a Location (also on global_start)

$vbulletin->url = $thisserverprotocol.$_SERVER['SERVER_NAME'].'/xlogin.html';

But that didn't work at all.


1a) What's the best way to check for non-logged in users?
1b) If I want to do location:, where should I hook?


2) How to submit that login form to vBulletin
I got a form to work by copying the rendered html from the cpanel login, and modifying the paths.
But that's bringing in a bunch of JavaScript seems like overkill. Is there a simple way to have a form submit to login?

3) An abbreviated custom registration form.
The email address will be passed in the URL, so I'll just have them fill in a handle and password.
I can write a record to the DB myself, but i"m sure there's a nice call I can make to create a user.
Could someone point me in the right direction?

These are the final features needed for this site, and need to be resolved ASAP.
Any help is appreciated.