Coconut milk: add it at the end. If you have to add it in the morning, whisk well before serving and if it's split it will come back together.
Eating at different times: leave the broth in the crockpot and whisk before each bowl. Refrigerate the beef and rice if they'll be out longer than 2 hours.
Gluten-free: use coconut aminos or tamari instead of soy sauce, and check the labels on your broth and sriracha.n.