Yes, all Authorize.net transactions (CIM or otherwise) may be rejected if they suspects it's a duplicate (same amount on same card very quickly).

For the saved billing address auto-populate... it works for me. What browser are you using? Do you have JS enabled? Can you use Firebug to help me track down the JS problem?

You're right, billing address fields aren't required currently. That is a limitation I should fix one of these days... But you can always require these fields in your Authorize.net account setup, so that transactions that fail address verification are rejected. Not as good, I know, but it works.

Recurring fee charging should work with the Billing and Payment checkout panes. It's just not a configuration that has been as well tested, so I'm not surprised there are some bugs with it. I'll take a look.