Place the steak and chicken each in a zip seal bag.
Pour 2/3 cup of the marinade into each bag.
Take care to remove as much air as possible and seal the bags; shake well making sure the meat is thoroughly coated.
Marinate for 1-24 hours.
Skewers
If using bamboo skewers, soak in water before assembling so they don't burn while grilling.
Remove the steak and chicken from the marinade.
Layer the steak, onion, and bell pepper pieces; repeat for the chicken and sausage skewers.
Layer the vegetable skewers with onion, mushrooms, bell peppers, and zucchini.
Chimichurri
In a medium bowl, add the shallot, garlic, jalapeño, bell pepper, red wine vinegar, and salt; whisk together and let stand for 10 minutes.
Add the fresh cilantro, fresh flat-leaf/Italian parsley, and fresh oregano leaves to a food processor, pulse or mix and add the olive oil.
Once the herbs have reached the desired consistency, chunky or pureed, pour into the reserved bowl and mix together.
Cover and let stand until ready to use.
Assembly
Heat grill, once hot reduce flame to medium low.
Place the skewers and grill on one side for about 6 minutes for meat and 4 minutes for the vegetable-only.
Flip the skewers, and cook an additional 3 minutes if you want all sides seared, or 6 minutes for only two seared sides. 4 minutes or until cooked to desired doneness.
If searing all sides, rotate every 2 minutes on each side or until cooked through for meat skewers and every 1 minute for the vegetable-only skewer.
Exact cook times will be determined by the grill and thickness of meat and vegetables; adjust cook times accordingly.
Remove from grill and serve immediately with chimichurri.