Regarding the use of your cc for TER VIP, as long as you don't have a problem with someone else seeing a charge on your bill that you might have to explain, it is fine.  I get my cc bills electronically and don't print them so there is no concern.

I do appreciate gentlemen letting me know they've given my name as a reference to someone or if they're posting a review. But unless she specifically states she requires such, a "heads up" is helpful, but isn't absolutely necessary. However, if she has no other reviews yet, it may be because she doesn't want any -- in that case, yes, you should ask first.

Make sure to give the other prospectives the appropriate contact info for the ladies you want to act as your references. For example, I'd be peeved if someone gave my phone number to another lady, since I don't like to make it public. When in doubt, it's best to ask which method (phone call, email, PM) she prefers to use for giving references.