Ni-doms are not scatterbrained like butterfly-chasing types, but they are spacey, and can be one of the spaciest of all types. If by scatterbrained you mean lack of awareness to the external world, then they are absolutely scatterbrained.
You mention "faking it" with people as an example of Fe. I don't think people with strong Fe consider their external connection fake at all. When their responses are not authentic to their own inner desires and needs, it is often because they are choosing to prefer the requirements and values of the external world over their own, and so it is not "fake" in the least. Fe dom/aux tends to pay attention to external subjective systems of values, people, emotions, etc. They desire external peace and harmony and can avoid conflict at great personal cost. When Fe enters into conflict it is either because they are working to re-establish external harmony. For myself, I pay a significant cost with each conflict I enter into.
I believe that Ti deconstructs and Te constructs. Ti values its inner logic structures and conceptual efficiency while Te seek to implement external efficiency. Ti is the theoretician, Te is the engineer. Ti will focus on thinking about internal systems, while Te will focus on thinking of external systems.