Preheat the oven to 425 degrees. Toss the eggplant, bell peppers, onion, and garlic with the olive oil, salt, and pepper on a large baking sheet. Roast for 25 minutes, turn with a spatula, add the cherry tomatoes and roast another 20 minutes. Meanwhile, cook the orzo in boiling salted water for 7-9 minutes, until tender. Drain and transfer to a large serving bowl. Add the roasted vegetables to the pasta, scraping all the liquid and seasonings from the roasting pan into the pasta bowl. For the dressing, combine the lemon juice, olive oil, salt and pepper and pour on the pasta and vegetables. Do not add it all at once. I find that's too much dressing - you can always add more. Let cool to room temperature, then add the scallions, pignolis, feta, and basil