@ericm First, if you want a really strong Jalapeno taste and some heat then I would recommend either more seasoning than recommended (though be slightly careful with this, something around 10-15% more) or add jalapenos.
For the Encapsulated Citric Acid, if you are using it then you need to go right from the smoking to the stuffing, holding it overnight could allow the Encapsulation to break and leak the citric acid into the meat too soon. However you also don’t want to hold the meat and then add the ECA as the meat will start to set up and could break your stuffer when you try to stuff it into the casings. My recommendation would be to cut back slightly on the ECA and still stuff immediately.
Cooking to 170 will not create any real problems other than drying the meat out a little, if you are happy with the moisture and texture of your snack sticks with your current smoking schedule I say keep with it!