This just came up a few days ago. Similar situation with precooking one meat, Chicken in this case then adding other Raw Chicken, Cornish Hens on top... So here is my Response...
It just don't matter! Lets say you cook the Chicken for 2 hour, then add the Raw Hens because they only take 1 hour. The Hens are just GUSHING Bacteria laden juices all over your Chicken or Ribs, Butt, Brisket, anything in the Smoker. From what you have read and people keep posting, you think, " OH MY GOD I AM GONNA DIE! "
WRONG!!!!
Those juices are dripping on " 225+°F " Meat! Just how long do you think the Bacteria has to live!?! Seconds? Let's say they are Super Bugs
...A Minute or Two? On top of all this, you are going to Rest the HOT Meat you are taking out, the Surface will STAY HOT above 140*F for the next ONE TO FIVE HOURS! What kind of Bacteria do you all keep talking about that is soooo Dangerous that it will survive All Of The Above!?!
Again... It just don't matter what you put on top of what, the heat will kill it!...
...JJ