Full list of the capabilities of human brain
The length of your question and it's tags make it quite confusing, however what you mentioned about the brain processing tasks sequentially and then hitting an efficiency bottle-neck when using conflicting resources reminds me of the research of Neils Taatgen.

He uses a cognitive model called ACT-R to do computer simulations to predict what efficiency bottle-necks a person might experience. His research might help clarify some theories you have.