If I have a free bag to check in I will just bring an empty one just in case to bring stuff back. Usually I fly south west which has two free bags so I put a filled smaller luggage inside a larger one so it's easier to handle.

Autocrat or eclipse coffee syrup is great and has a long shelf life. Some places will also have Dave's Coffee syrup which is also great and made from real sugar instead of corn syrup. Pizza strips should be fine for a flight since they are kept at room temperature anyway, I took some to Seattle once myself. Try Clamcakes while you're here if you like them they sell the mix for the batter so you can make them yourself at home. Biscotti, egg and wine biscuits from local Italian bakeries also travel well.