For the marinade:
1) In a medium bowl, combine the marinade ingredients.
For the saffron orzo:
1) In a large pot, bring the chicken stock to a boil over high heat. Reduce the heat to low, bringing the stock to a simmer. Add the saffron, stir, and allow the saffron to bloom, about five minutes.
2) Return the heat to medium and the stock to a boil, then add the orzo and cook until tender but still firm to the bite, stirring occasionally, about 8 to 10 minutes.
3) Drain orzo and transfer to a large bowl. Add the olive oil, lemon juice, salt, pepper, and parsley. Toss to combine.
For the grilled meat and vegetables:
1) In a large bowl, combine half the marinade with the chicken breasts, chicken thighs, and shrimp. Toss to combine. Cover and let marinate for at least one hour. If marinating for longer than one hour, make sure to refrigerate.
2) Place a griddle pan over medium-high heat or preheat a gas or charcoal griddle or barbecue. Brush the corn with reserved unused marinade and wrap in foil. Toss the mushrooms with 55ml of the reserved unused marinade.
3) Griddle the chicken breasts and thighs to an internal temperature of 75°C, about seven minutes a side. Griddle the corn inside the foil, for about five minutes a side. Griddle the peppers for about five minutes a side. Griddle the shrimp and the mushrooms, about two minutes a side. Brush the griddled peppers with the last of the reserved unused marinade. Slice the peppers and mushrooms before serving, if desired.
4) Arrange griddled meats and vegetables over the saffron orzo on a large platter and serve immediately.