For the coconut rice: Add the oil to a medium saucepan with a tight-fitting lid and set over medium heat. Add the rice, stir to coat in the oil, and toast for 2 to 3 minutes. Add 1 1/2 cups water, the coconut milk and salt and stir to combine. Simmer, uncovered, until the liquid reduces to the level of the rice. Cover the pot and reduce the heat to low. After 15 minutes, stir the rice, re-cover and set the pot off the heat for 5 minutes. Fluff the rice with a fork and add the cilantro and scallions.
For the jerk sauce: Heat the oil in a medium saucepan over medium-high heat. Add the garlic, ginger, Scotch bonnet and scallions and cook until aromatic, about 2 minutes. Add the allspice, cinnamon, nutmeg, bay leaf and some salt and toast it all for about 15 seconds. Stir in the chicken stock, brown sugar, soy sauce, thyme and lime zest. Bring to a simmer and cook for 5 to 7 minutes. Finish with the lime juice and half of the cilantro. Pour half of the jerk sauce into a small bowl for serving and set aside. Reserve the remaining sauce for brushing during grilling.
For the lobster: Preheat a grill or grill pan to medium-high heat. Spoon the reserved jerk sauce over the flesh side of the lobster tails and place them on the grill flesh-side down. Grill until nicely charred, 5 minutes. Flip, then spoon more jerk sauce over the lobster meat, and grill 5 minutes more or until cooked through and the meat is starting to pull away from the shell.
This is a great family-style plate. Line a platter with the coconut rice and arrange the grilled lobster tails on top. Smear each tail with some of the butter and pour over the remaining jerk sauce. Garnish with the remaining cilantro and scallion greens.