Like everyone new to QB and edspecially bank linking I am going to suggest the same as I always do.

Enter your transactions as if there were no bank feeds. Enter the card charges against teh credit card type account you will have set up. After turning on Inventory in the charges you can specify amounts and it will add to your inventory. Both of your issues will be accomplished in one set of transactions. Charging to a credit card is a current expense or inventory purchase while paying down the card balance is only cash flow, neither income nor expense.

Use the feeds as a confirmation, do not depend on them for your transactions. You will be presented with a greem match when yoru entered transaction in dollar and date corresponds to something in the feed - it is still up to you to determine if it is correct, but entering data first is better than editing a feed item and then saving .