For the meat:
Preheat oven to 300 degrees.
Generously salt & pepper the pork roast, then set it on top of the onions in your covered roaster.
Pour the can of chipotle peppers over the pork (include the sauce). Pour in both cans of Dr. Pepper. Add brown sugar to the liquid & stir in.
Place lid tightly on pot, then set pot in the oven. Cook for at least 6 hours, turning roast 2-3 times during the cooking process. Check meat after six hours; it should be falling apart. Use 2 forks to test. If it doesn't fall apart, return to the oven for an additional hour.
Remove meat from the pot, and place on a cutting board of other work surface. Use 2 forks to shred meat, discarding large pieces of fat. Strain as much of the fat off the top of the cooking liquid as you can & discard it. Return the shredded meat to the cooking liquid, and keep warm until ready to serve.
For the slaw:
Combine the coleslaw mix & sliced jalapenos in a bowl. In a separate bowl mix mix, milk, mayonnaise, vinegar, sugar, salt, & cayenne pepper. Pour over coleslaw mix. Toss to combine. Cover & refrigerate for 2 hours.
Before serving, toss in cilantro leaves.
For the sandwiches:
Butter both halves of your rolls, then brown them on a griddle or skillet until golden and crisp on the surface. Load up each sandwich with shredded pork, & then REALLY load them up with the slaw.