RewriteRule causing internal redirect limit error
Start by getting the base site working at your Drupal domain then slowly add Rewrite rules. First remove everything you've added to the .htaccess files and elsewhere, upload the site to the directory you want and see if you can access it.

http://www.example.com/sites/default/files/staticsite


If that doesn't works then the problem is probably the current .htaccess configuration (docroot or files directory).  If it does work, move on to the next stage.

The next step is to get your custom hostname working. This seems pretty straight forward from the Acquia docs:

RewriteCond %{HTTP_HOST} ^subdomain\.example.com\.com$
# Don't loop anything targeting the actual mask directory, to allow
# for linked scripts, stylesheets etc in the static HTML
RewriteCond %{REQUEST_URI} !^/sites/default/files/staticsite/
# pass-through the matching file from beneath /sites/default/files/ and stop processing
RewriteRule ^(.*)$ /sites/default/files/staticsite/$1 [PT,L]


Important: The above needs to be inserted before the following. If it's not, non-file requests (such as directory index / ) may redirect to index.php instead.

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !=/favicon.ico
RewriteRule ^ index.php [L]


If that works, start adding the other domains one by one and testing.