WordPress 3.8.1 Multisite subdomain dashboard inaccessible

The Setup
I have just completed a fresh install of a WordPress 3.8.1 Network (Multisite) using subdomains. It currently has 2 sites, the primary install and a subdomain. The Registrar is GoDaddy, but the URL has been pointed to the nameservers directly. I have added the DNS wildcard using cPanel. The .htaccess is configured with the rules supplied by the Network setup, and the wp-config file has been edited as per the setup instructions. I have cleared my DNS, flushed the cookies and given appropriate time for propagation.

The Issue
I can view both sites (using the individual domains) and I can login to the primary install’s Dashboard (using a super user account). I cannot, however, login to the subdomain’s Dashboard. All I get is a 404 when I try to go to the dashboard.

The Ask
I have read countless posts, most refer to pre 3.3.1 framework that includes the MU Domain Mapping Plugin (although I did try it without success). And I have read the codex, but it too seems dated. This leads me to ask the following:
1. Does the MU DNS Mapping Plugin work with 3.8.1
2. Do I need an entry in my .htaccess file to set the upload location?
a. # uploaded files
RewriteRule ^([_0-9a-zA-Z-]+/)?files/(.+) wp-includes/ms-files.php?file=$2 [L]
3. Should my subdomain site settings tab have the following or blank entries?
a. Upload Path: wp-content/blogs.dir/3/files
b. File Upload URL: http://subsite.primarydomain.com/files

Setup steps
1. Went to my domain host (GoDaddy) and set the nameserver for “domain.com” and “domain2.com” to my Hostgator settings.
2. In HostGator Cpanel I created the Addon Domain for domain.com that points to public_html/domain.com
3. Still in Cpanel, I setup a wildcard subdomain for domain.com that points to public_html (not redirected)
4. Still in Cpanel, I set up a subdomain entry for “domain2.domain.com” that points to domain.com’s public_html and NOT public_html/test1 (which is the default for subdomains and not redirected)
5. Installed WordPress under public_html/domain.com folder
6. Added the following:
Add the following to your .htaccess file in /, replacing other WordPress rules:

RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
# add a trailing slash to /wp-admin
RewriteRule ^wp-admin$ wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule ^(wp-(content|admin|includes).*) $1 [L]
RewriteRule ^(.*\.php)$ $1 [L]
RewriteRule . index.php [L]

Add the following to your wp-config.php file

/* Multisite */
define( 'WP_ALLOW_MULTISITE', true );
define('MULTISITE', true);
define('SUBDOMAIN_INSTALL', true);
define('DOMAIN_CURRENT_SITE', 'domain.com');
define('PATH_CURRENT_SITE', '/');
define('SITE_ID_CURRENT_SITE', 1);
define('BLOG_ID_CURRENT_SITE', 1);

7. Log in to wordpress site that has the “multisite” feature set up and installed the “WordPress MU Domain Mapping” plugin and network activated it.
8. Went to “my sites”>>”network admin”>>”sites”
9. Added a new site with the “site address” as “domain2.domain.com” and title as “test1” and email address of my super-admin.
10. Went back to my main wordpress dashboard, went to “my Sites”>>”test1″>>”dashboard”
a. I get a 404 error from HostGator
11. Went to domain.com/wp-admin
a. I get a 404 error from HostGator
12. Went to “My Sites”>>”test1″>>”visit”
a. I get a replica of domain.com at url: domain2.domain.com
13. If it was working, I should be able to Log in to test1 dashboard!
14. Go to “tools”>>”domain mapping” (still in test1’s site’s dashboard
15. Enter “domain2.com” in the text field and check the “Primary Address” button, then clicked “ADD”
16. Check the URL, and have “domain2.com” go to “test1”.