Isaac: do you really want to work for people who claim to be vegetarians yet eat fish? That is, who are not honest in simply stating, "We don't eat meat or poultry," but couch their preferences in trendy terms of supposed health or morals?
Sorry to rant like this, but it's more than a semantic distinction to me. If you are a vegetarian, you do not eat flesh; if you eat any kind of flesh that had to die first, you are NOT a vegetarian.
But to answer your request:
1st course: Mushroom napoleon with bell pepper caviar accompanied with cilantro oil
Do you mean using mushrooms for what would normally be the pastry layers? If you slice roasted portabello caps on the bias, you can get pretty large, thin slices. And what for the "cream filling?" Whipped herbed goat cheese, perhaps? Yum. In any case, this should be absolutely gorgeous to look at (red bell peppers, right?).
2nd course: Carrot and rhubarb stuffed ravioli with caramelized shallots with a corn and pea coulis
Is your idea to offset the tartness of the rhubarb with the sweetness of all the other components? I might do the dish in reverse; that is, stuff the ravioli with a corn-and-pea puree, sauce it with the carrots and rhubarb, and garnish with the shallots. There's just something about the idea of savory rhubarb-filled ravioli that doesn't appeal to my palate. However, whichever way you do it, the colors will be really nice.
3rd course: Smoked tomato, arugula, and radicchio salad with an orange- honey vinaigrette
Unfortunately, I don't think the colors will work here: clashing shades of reds and orange seem a bit too busy. And, if you use a sweet-tart sauce for the ravioli (as I suggested above

), you're repeating that flavor here. Why not take full advantage of tomatoes and do an heirloom tomato salad with arugula and a smoked tomato vinaigrette? The vinaigrette uses the less-than-perfect-looking tomato specimens.
The next two courses of the menu sounds very, very good; no comments there.
6th course: Trio of crème brule (saffron, lemon grass/ and berry)
Consider panna cotta instead of crème brûlée. If they want light and healthy, that's a better choice. You can do all the same flavors. Just find out if they eat gelatin.
Best of luck, and keep us posted.