The rule is you may use one code at a time, unless you have the $10 off for purchasing the club. So you should be able to plug another one in as well. The $10 off is automatic, and just appears on the next order you make after the club. You probably wont be able to use the free shipping and 10% off at the same time.

There is NO Advance warning system on retiring items. It would be nice of them to do this, but there isn't at the time. AG really needs to inform ahead of time when they're going to retire something.

Monthly Specials, for the most part, are them getting rid of extra stock. Items on the Sale page ARE retiring. Get them while they're on there, or you'll have to get them by some other means (AGP, ebay, etc.). The 2 outfits on the Sale page, the Beachside and the Spiderwitch are retiring (the latter has sold out, and is, presumably, retired). Both the Cheerleader and the Molly outfit on Monthly Special should be retiring soon, but normally, them being on Monthly Special is not an indication of that, both of those are just quite old.