Veracruzan Seafood Cocktail (Vuelve a La Vida)

Ingredients

• 3 bay leaves
• 1 head garlic, halved crosswise
• 1 lb. large shrimp, peeled and deveined
• 1 lb. cleaned calamari, bodies cut into 1/6″-wide rings, tentacles halved lengthwise
• 12 oz. boneless, skinless red snapper filets
• 3⁄4 cup fresh lime juice
• 2 tsp. dried oregano, preferably Mexican
• Kosher salt, to taste
• 1 lb. plum tomatoes, cored, seeded, and finely chopped
• 1 cup ketchup
• 1 cup tomato juice
• 1 cup pimiento-stuffed green olives
• 1 cup finely chopped cilantro
• 1⁄4 cup Worcestershire
• 6 tbsp. olive oil
• 2 serrano chiles, stemmed and thinly sliced
• 1 habanero or Scotch bonnet chile, stemmed, seeded, and minced
• 1 medium white onion, finely chopped
• 16 small oysters, shucked, juices reserved
• 16 small clams, shucked, juices reserved
• 2 avocados, thinly sliced
• Saltine crackers, for serving