I think you can use the coconut oil to brown the chicken. I have not used ghee for cooking, so I am not sure, but probably you could use that for browning as well.

It's possible that ghee has a low burning temp (not sure how it compares to butter), but I am just guessing, so watch over it and don't turn the temperature on super high. Coconut oil does have a fairly high burning temp, so it might be the safest choice.

This is a recipe that sounds like it makes more than four servings (4lbs of chicken plus a pound of shrimp? that's 1.25lbs of meat per serving???) But... assuming you don't have the shrimp, you've probably got a pound of chicken between those two chicken pieces...

So:

You can probably brown the chicken pieces with a 2 or 3 tablespoons of fat (either the ghee or coconut oil) and you probably want to make sure it's cooked through instead of just browned, because you are not cooking it in the slow cooker

I would say cut the sauce ingredients by half so you aren't making a full batch of sauce for far less protein. Instead of putting it all in a slow cooker, combine it all in a larger pot, bring to a boil and then simmer on the stove for the 20-30 minutes directed at the end. Although the longer you let it simmer, the more the flavors will develop.

If you do have shrimp, I'd saute them with the chicken, or when you cook the chicken, but that's just me. You can add them in for the 20-30 min simmer as the directions intend but then make sure they are actually cooked through before you eat.