Tear the chiles into pieces; discard the stems and seeds. Place in a bowl.; add boiling water just to cover (place a plate on top to keep submerged). Let soak until tender, about 30 minutes. Transfer the chiles and 1/2 cup of the soaking liquid to a blender. Add 2 pineapple slices, 1/4 cup pineapple juice, the orange juice, onion, brown sugar, cumin, 1 tsp. salt and 1/4 tsp. pepper. Blend until smooth; transfer to a large bowl.
Rinse the chicken inside and out. Pat dry and add to the bowl with the chile puree, turning to coat the skin and fill the cavity. Cover and refrigerate for a least 3 hours or overnight.
Transfer the chicken and marinade to a large, lined slow cooker. Cover; cook on high until the chicken is tender and an instant-read thermometer inserted into a thigh away from the bone registers 165 degrees , about 3 1/2 hours.
Meanwhile, using a food processor, fitted with the shredding disk, shred the cabbage and carrots. Transfer to a bowl; mix in the scallion greens. Chop 4 pineapple slices; toss with the cabbage mixture.
Transfer the chicken to a plate. Pour the juices and marinade into a 1-qt. glass measuring cup; let stand until the fat rises to the top. Skim the fat from the juices. Transfer the juices to a medium saucepan; simmer until reduced to 1 cup. Using 2 forks, shred the meat. Discard the skin and bones.
Meanwhile, mix the mayo and 1/4 cup pineapple juice into the slaw; season.
Add the chicken to the reduced chile juices; cook until heated through. Warm the tortillas. Place about 1/4 cup chicken on each tortilla. Top with the slaw and crumbled goat cheese.