If you checkout annonymously... tough you can't see your order status (I think this is just how it works and what customers would expect?). You should login first and then checkout if you want persistence on your part of seeing the orders.
Well you can set a cookie that indexes back to the order ? So as long as they don't clear their cookies or you clear the link then ok.
When they "pay" you know the account that made the payment so you can always pair it back up.
Not sure because if they checkout in anon mode its not associated with any user... and if you login thereafter the order is not associated even though the account names that paid/logged in match.... Not sure how hard that is because each system will be different with different database designs and db key constraints, can you reassociate anon orders based on creating an account? dunno
When they "pay" in anon mode, you should create an account for the user that paid (ie: the from field in the memo) and associate the order with that new account.
That goes back to what I was talking about earlier, now they will have no way to relog back in to see their order status once they go away and come back... they dont know their pw... only way to re log back in is to go through the payment gateway again... ugly.. there should be a separation of concerns because if they are already logged in it doesn't create an account for you...
Only way is if you have another button to allow them to login via bitshares... but because there is no seperation of concerns you have a case where you would have the payment gateway autocreate/login for you and then no way to login because this shopping cart is so simple that you can't hook in these oauth login plugins or a system like ecwid which is a hosted shopping cart that uses authorize .net to post order data back and forth and a limited API to talk to the cart.