I have to second this. Empty stomachs and alcohol are not a good mix. If you go with the heavy finger food route, look to get more of the less expensive items, especially if they are filling. Pita chips and hummus instead of shrimp. You want quality as in good quality pita chips and hummus. You don’t need ritzy. I always tell people to avoid shrimp anyway – it’s too expensive per piece, and people go crazy for it. Aunt Martha could take out half the shrimp platter!
You might also want to find out if the caterer offers a choice of pricing of an open bar. Two standard ways are on consumption and per head. With on consumption, you know up front that you will be charged a certain amount for every bottle the bar uses. Per head, obviously, is a per person cost, usually broken down per hour. So $X per person per hour, no matter how much or how little each person drinks. Some places will exclude children from the total number of attendees in determining the head count, but beyond that, it’s $X for every person in the room. You can’t pick and choose by saying Uncle So-and-So doesn’t drink – the rationale for the caterer is that some folks will drink a lot and some will drink a little, making for an average consumption that is reasonable.
My general rule of thumb in event planning is that if you suspect guests will drink little, on consumption is the better deal, and if you think people will drink a lot, go with per head. Also remember that people tend to drink more than they might otherwise at a wedding. Unless you have a lot of people who never drink, say for religious reasons, you might go through more alcohol than you expect.