You can make items out of them if you have the recipe, gold, and needed items like the ones stated.
You can forge them through Back Alley Bargains and anything incomplete will show up red.
Alternatively, you can sell them for gold.
Oh and keep the gold.
Most of the loot that you've mentioned can be used in Recipes dropped by the animated.
Specifically, Wing Tree Leaves, Branches, Flamingo Feathers, and Screws can be used to craft Alchemist Cases, and Philosopher's Caches in Alchemy, along with being used for Recipes.