This is basically what the brain already does, but ramped up to 11 and in control of the conscious mind.
The problem is that this requires a very specific mind. During development your brain makes millions of connections with other parts of the brains, then at some point it starts to purposefully remove many of these, leaving the most used neural pathways and optimizing those. This accelerates thoughts as less energy and time is spend on what the removed pathways send around. Unfortunately this also means that if you want to use a brain segment normally used for storing a skill or memory for something else that there are few neural pathways connecting them. You would skip the neural pathway pruning and end up with a specific disorder: Autism. Now unlike popular opinion most people with autism arent unsocial people who scream at everything, in fact most people with autism are so good at learning to fake social interactions that they arent discovered even when they get unspecific psychological tests.
Then there is your idea for less sensory filtering. A suggestion is not to include that but shift it to a more specific sensory filtering, something the body already does. Talk about lice in front of people and the brain starts letting signals about itches through to the brain, signals that were filtered before. Gate theory (https://en.m.wikipedia.org/wiki/Gate_control_theory) is a part of this system.
Funnily enough, less sensory filtering is also a part of autism. Due to the "unnecessary" neural pathways and less filtering the brain is more easily overloaded, stuck trying to sift through all the information its bombarded with and unable to process more. The classical screaming autist that is practically a meme nowadays is one way this overload can express itself, its a (partially successful) coping mechanism to reduce the amount of sensory input, if only by making said input move away. More common though is unresponsiveness to outward stimuli or getting stuck performing a repetitive task to engage the conscious until the subconscious has figured everything out again.
Tl, dr: yes this is possible if you change the "less sensory filtering" into "more specific sensory filtering" and are willing to accept a partially autistic mind. Since your brain development would not have autistic filtering it would only think like an autist and suffer less from the negatives.
Ignore the first point of "autistic people rarely lie", autistic people have trouble learning how to properly lie and get caught when they do, so they will stop trying to lie and tell truths. Your person would be able to learn lies.