How would I modify this recipe to make it in a slow cooker?

Every slow cooker is different, so, the timing will depend on yours and your pork. I would simply add everything to the cooker except maybe the peas. I'm not sure why the recipe author held off on the coconut milk, so again, my method would be to add it in the beginning. I make chicken adobo in my SC and the coconut doesn't do anything weird. Chunks of boneless pork ribs become tender in my slow cooker in 4-4.5 hours. Mine runs a little hot. Maybe add the peas for the last 30-60 minutes. You don't want mushy peas.

That is what would work in my slow cooker. Good luck. :) Recipe sounds delicious.