In a small saucepan over medium-low heat, combine the olive oil, garlic, bay leaves and thyme. Cook 15 to 18 minutes or until garlic is tender and just slightly golden. Let cool to room temperature. 

In large bowl, toss farro, garbanzo beans, cucumber, tomatoes, scallions, parsley and mint with lemon juice, 1/4-cup of garlic-herb oil and 1/4 teaspoon pepper. Toss mushrooms with remaining 1/4 cup of garlic-herb oil; let stand 5 minutes. 

Heat grill to medium. Sprinkle mushrooms with 1/2 teaspoon of salt and 1/4 teaspoon of pepper. Grill mushrooms, 2 minutes per side, or until tender. Transfer mushrooms to cutting surface; cut into 4 to 6 slices. 

Brush both sides of pitas with olive oil; grill pitas, one minute per side. Transfer to cutting surface; cut each pita into 2 wedges. 

In small serving bowl, combine yogurt, feta and 1/4 teaspoon of pepper; blend well. 

Fill pitas with farro salad and mushrooms. Top with feta-yogurt sauce.