I know you're through with this, but for people just tuning in, when you have to feed just one vegetarian in a group of people, a Mexican buffet line cannot be beat. Make it "assemble your own", then you don't have to worry about whether the guest is vegan or not. I put out both soft flour tortillas and crisp corn ones (either taco shells or tostadas). I make a spanish rice without meat. Refried beans (I make sure they're vegan if that is the case).
A bean chili. Depending on how many people and who they are, it can be ground beef, pulled pork, beef, or chicken or more than one. Grated cheese, several salsas. If the guest is vegan, I'm very careful about the ingredient list on the prepared foods I use (sometimes tortillas, beans, etc, are cooked with lard). This allows your guests to pick & choose. (My mother had a vegan freind, and she herself doesn't eat meat, although she loves gravy and boullion, etc; she just can't tolerate the texture of meat because of health problems, so I'm experienced at getting around it all!).
A good twist on ratatouille is to grill all the vegetables. Yumm.