50/50 cider vinegar/ketchup. Add salt and red pepper flake to taste, use that base to add other flavors. Bring to just a simmer then off heat stir in a blob of butter to make it a little thicker and richer. I use that on pulled pork and it is good stuff.
I have eaten plenty of roadkill! Not run over flat but lots of car hit deer have graced my freezer over the years. A few pheasants, a turkey, couple squirrels that committed suicide by sticking their head up...
You could experiment with a mayonnaise/mustard/hot sauce BBQ sauce... I have played with it for a savory sticky coating but nothing I like quite yet(need to work on spices. I use chicken leg quarters to test).
Cook he top by itself, cook each seafood separately, combine in the serving dish and top with the precooked crust. Place the puff pastry on parchment to cook it, cut first to the right size for each serving.
Chuck roll is very forgiving and when done low and slow it shreds just like a pork butt. I take it to 198 internal. Lower left was a chuck roll I cut into fourths so each roast was about 8 pounds... cooked for 18 hours.