Preheat the oven to 425°F (220°C).
On a baking sheet, toss the diced eggplant, red and yellow bell peppers, diced red onion and minced garlic with 1/3 cup olive oil, 1 1/2 teaspoons Kosher salt and 1/2 teaspoon black pepper in a single layer.
Roast the vegetables for 40 minutes, stirring or turning once halfway through, until nicely browned and tender.
While the vegetables roast, bring a large pot of salted water to a boil and cook the orzo for 7 to 9 minutes until tender; drain and transfer the cooked orzo to a large serving bowl.
Add the roasted vegetables to the bowl with the orzo, scraping any browned bits and juices from the baking sheet into the bowl.
In a medium bowl, whisk together 1/3 cup lemon juice, 1/3 cup olive oil, 1 teaspoon Kosher salt and 1/2 teaspoon black pepper.
Pour the lemon dressing over the warm orzo and vegetables and toss to combine; let the mixture cool to room temperature.
Stir in the sliced green onions, toasted pine nuts, diced feta and basil strips; taste and adjust seasoning if needed, then serve at room temperature.