I don't think you need to announce "vegan menu" because some people are going to object to the word vegan even if it's something they would normally happily eat and enjoy.
If you're offering a choice on the menu, you need to give enough information to let people choose properly - so "basil pasta with tofu" is better than "basil pasta" and "flax seed and cashew pizza" is better than "pizza".
At the actual meal, if you provide a varied selection of items and information about the contents, you're being a good host, even if there are people who will turn up their noses at everything, or not be able to eat due to serious dietary restrictions. In your case, I do think you need to accurately label food that's made with non standard or substitute ingredients, so people with restrictions know what's going on (like indicating the spaghetti sauce is made with wheat gluten or soy based meat substitute rather than ground beef). People with allergies and serious restrictions will know how to prepare for a wedding meal, and how to ask about ingredients. Picky people are not going to die if they have a meal that's not prepared to their exact tastes.
My personal advice, though, if you want to design a vegan menu with broad appeal, is to avoid leaning too heavily on vegan substitute ingredients in normally non vegan dishes (soy cheese, tofu as a meat substitute, seiten, etc), and focus on naturally vegan dishes. I'm not at all a picky eater, enjoy good vegan food, like tofu, and will generally eat what I'm served, no matter how weird (and I've been to a lot of Chinese wedding banquets, so when I say weird, I'm talking things like stewed chicken testicles). But I still regard something like pizza with soy cheese and vegan pepperoni as a badly made pizza.