I cook a big Easter dinner every year for a group that includes several vegetarians. This year, I'm doing ravioli- you can make your own pasta or buy sheets of fresh. I'm filling mine with a pea pesto and ricotta, but I bet you could omit the cheese for something equally tasty.

asparagus frittata, beet salad, hot cross buns, strawberry tart for dessert.

I tend to use the holidays as an excuse to make my favorite meals with exotic or somewhat pricey ingredients; like tapenade on crisp baguettes, grilled shitake mushrooms with cornbread stuffing, and a fresh spring green salad topped with nuts and a light vinagrette.

I think of really springy ingredients. Here are some spring veg/vegan dishes I make a lot:
-How about a risotto made with peas, asparagus, and baby carrots with an extra dallop of olive oil (I often make lighter risottos without butter or cheese, and as long as you use good stock, the creaminess of the rice really tastes rich and perfect).
-Pea soup with mint
-A fritatta made without milk and with butter (you didn't say folks were vegan...) and with lots of spring veg
-Fennel, arugula, and orange salad
-Citrus fruit salad
-Arugula and parsley pesto with pasta (I always make my pesto without cheese anyway)

As a vegetarian person I find holidays to be newly frustrating because my family doesn't understand a holiday meal that doesn't include a ham or a turkey. however, since there's more than one veg at dinner this year I'm doing some special things:
-serving special appetizers that are healthy and veg friendly for EVERYONE! from hummus to spinach dip with veggies etc. and perogis.We of course also have deviled eggs.
-serving a really beautiful salad, bread with goat cheese for those who eat dairy
-a broth soup (mine is just a conglomeration of fresh vegetables boiled etc
-risotto with whatever they have fresh on saturday. Probably peas, maybe asparagus? and mushrooms
-some kind of yummy dessert (chocolate cake?)

I'm Greek and a lot of the dishes that accompany the Easter meal are vegetarian and seasonal. Tzatziki, fava spread, roasted potatoes in olive oil and lemon, artichokes "a la polita" (http://www.greek-recipe.com/static/content/Artichokes_a_la_polita.html), and a simple chopped romaine salad with fresh dill, cucumbers, feta and a simple olive oil/s&p/lemon dressing (I embellish it with avocado sometimes). I'm not sure how much this one is cooked for easter, but it could be a good protein source:

Greek Black-Eyed Pea Salad
http://greekfood.about.com/od/soupsstews/r/mavrom_capers.htm

Quiche (tofu if they're vegan), or this chickpea tart (minus the cranberries; that way it feels more "spring-y") for a central dish if you're looking for one; if not, just make sure most of your sides are veg-friendly without just being starches or vegetables. Sautees asparagus with almonds, a bulgur salad--that right there would be a complete meal. Good luck!

What about some kind of lentil soup or stew?

http://vegetarian.about.com/od/soupsstewsandchili/r/lentilsoup.htm
http://www.epicurious.com/recipes/food/views/Vegetarian-Lentil-Stew-134

My biggest pet peeve as a (former) vegetarian was people assuming I loved mushrooms, rice and tofu without asking first. ASK your friends what they like, then make it for them. More importantly, when I was a vegetarian, I *always offered to help the host cook or I would bring an extra dish because I think it is too pushy to force the host to cater to my vegetarian / allergy needs.

My family is vegetarian now, but that's not how I grew up. This year, I am trying to convert our traditional Easter to meal to one that we can all eat. Brunch: hot cross buns, vegan Canadian bacon & orange julius (orange juice+ice cream smoothie). Dinner: homemade seitan, scalloped potato, steamed asparagus, strawberry cheesecake. ;)

Hi Hilary,
I found lots of great ideas here: http://www.peta.org/living/vegetarian-living/Easy-Easter-Brunch-Menu.aspx
Here's a great vegan easter eggs recipe too: http://www.peta.org/living/vegetarian-living/Homemade-Vegan-Easter-Eggs.aspx

Good luck on your search.