here's my 2 cents
htaccess.
the problem here is the members area protection.
what is writing to your 1 htaccess file how do you let new people in how is the access controled by your avs service.
if avs 1 writes to htaccess then avs 2 writes to that may be a problem.
about traffic you may have to check and see if any of the avs services puts you on a link list. they should not be hotlinking from the inside.
on a paranoid note you may want to make sure they are not allowing others to see your content. as in create fake sites with your content.
