Your questions intrigued me all day, at least the first one did! Here are my thoughts:
1. Take the check he gave you, cash it and send the funds to pay down your credit card. When the payment is downloaded for reconciliation, just exclude it. Same for the purchase. When the lunch charge gets downloaded, just exclude it. That is my down and dirty way to deal with that. Alternatively, you could just categorize the meal as a misc. expense, and categorize the payment as misc. income. That way they cancel each other out. Fyi if you were the one who made the personal purchase on the company card, just categorize it as owner draw.
2. The amount you paid the contractor isn't exactly a bad debt. It actually is a payment to the contract for which you didn't get anything in return. You should process it as a regular payment to the contractor, and send him a 1099 at the end of the year.
I will add that for both issues, there are often multiple ways to deal with them. My general rule is: Can I defend it? Also, is it reasonably categorized, and is there a paper trail if you need it.
