Make the Vegetables: Fill the stock pot with water and bring to a boil. Stir in the lemon juice and salt. Fill the pasta basket with the broccoli rabe, cauliflower, mushrooms, zucchini, and squash. Submerge in the boiling water and cook, covered for 2 minutes. Remove the basket and refresh the vegetables under cold running water.
Transfer the vegetables to a bowl and mix with the pepper strips, artichokes, and olives.
In a blender, combine the vinegar, lemon juice, mustard, salt, and pepper. Mix on medium until completely blended. While the motor is running, slowly pour in the oils in a steady stream to make a smooth dressing.
Pour the dressing over vegetables. Add the basil and toss well. Chill for at least 2 hours before serving. Arrange on a decorative platter garnished with fresh basil and lemon wedges.