When planning a holiday party it's really fun to plan the desserts. Desserts just seem to be more party like but you can't have a meal of all desserts, especially on Halloween when the kids will already have an assortment of treats to choose from. For me, I try to plan healthy snacks and a solid meal for the day so that when my son does trick or treat, he's not gorging on sugary stuff. I'm grateful that he's not huge on the sweets (well wasn't as he gets older he eats more candy). I can fill him up with good food and since I always make too much, there's always some waiting for him at home if he gets hungry. He would prefer to snack on the "food" than the candy. He's also one who likes it when houses give out apples and he snacks on those.
One fun thing to add is finger food with sauces. You can make pretty normal sauces sound really gross with a few signs. Chicken strips can become werewolf or witch fingers (add an almond sliver to the pointed end for a fingernail if you so desire). Ketchup can become blood drizzled over the top. Or you can use sweet and sour sauce. Mustard, ranch or sour cream can become pus.
Slice up apples and serve them with raspberry, cherry or strawberry sauce/syrup for bloody fruit. A quick and easy fruit sauce - thin jam with a little water.
I, personally, avoid artificial colors. There are a variety of reasons why and everyone has their own - me, I figure there's enough junk in the candy that it's my job to balance it with good wholesome foods.
Creative labeling, and even some arranging, can make your every day dish something spooky.
Any red sauce can easily become blood. Don't forget spaghetti sauce. You can make breadsticks and twist them to give them a gnarled appearance and dip in spaghetti sauce. Decorate a pizza with large plastic flies and spiders and call it something yucky (a cheese pizza could become bloody bandage pizza - just don't make it so gross no one will eat it).