Before starting, wash and dry all produce. Preheat the oven to 450°F. Lightly oil the grill. While you prep, preheat the grill to 400°F over medium heat. Soak skewers in water, 5 min. Cut potatoes into 1/2-inch wedges. Add potatoes and 1 tbsp oil to a parchment-lined baking sheet. (NOTE: For 4 ppl, use 2 parchment-lined baking sheets, with 1 tbsp oil per sheet.) Season with 1/4 tsp (1/2 tsp) garlic salt and half the Montreal Spice Blend, then toss to coat. Roast in the middle of the oven, flipping halfway through, until golden-brown, 24-26 min. (NOTE: For 4 ppl, roast in the middle and top of the oven, rotating sheets halfway through.)

Meanwhile, quarter pepper lengthwise, then core. Quarter zucchini lengthwise. Zest lemon, then cut half into wedges (whole lemon). Add mayo, sour cream and lemon zest to a small bowl. Season with pepper and a pinch of garlic salt, to taste. Squeeze a lemon wedge over top, then stir to combine.

Using a strainer, drain and rinse shrimp, then pat dry with paper towels. Add shrimp, remaining Montreal Spice Blend and 1 tbsp (2 tbsp) oil to a medium bowl, then toss to coat. Thread 6 or 7 shrimp onto each wooden skewer.

Add peppers, zucchini and 1 tbsp (2 tbsp) oil to a large bowl. Season with pepper and remaining garlic salt, then toss to coat. Add peppers and zucchini to one side of the grill. Close lid and grill, flipping halfway through, until tender-crisp, 8-10 min. (NOTE: If zucchini cooks faster than peppers, transfer zucchini to a plate and cover to keep warm.)

When veggies are halfway done, add shrimp to the other side of the grill. Close lid and grill, flipping once, until shrimp are cooked through, 4-6 min.**Cut grilled veggies into 1-inch pieces.

Divide shrimp skewers, potato wedges and veggies between plates. Serve garlic-lemon sauce alongside for dipping. Squeeze a lemon wedge over shrimp, if desired.