That a 16-year old remembers such detail about age 3 seems… unusual. I don’t mean a memory here or there; this child remembers very specific experiences and the feelings he had about them when he was almost pre-verbal. Seems almost incredible.
Even today, I remember one "crazy conclusion" like the article talks about from I was very small (probably around 3). We lived near a river, which I inferred must be circular (like an ouroboros), because otherwise it would drain away. For some reason I can't exactly recall, I thought the town across the river was on the island this would form, and the town I lived in was along the outside edge. This of course meant that you could go to the center of the other town, but not to the center of our town.
I also have memories that were certainly from before I was 2 1/2 (my family moved then, so they stuck with me because that made them distinct). One of these memories is obviously real, but got "patched up" with some peripheral details from a little later in life. The memory was set outside at the bottom of the stairs of the apartment where my parents lived when I was born, the peripheral details of the design of those stairs and the setting beyond my immediate vicinity got replaced with those of different apartment building near our new house). I only realized this when I was 10, and we visited the town where I was born and went back to that apartment building.
Also, none of these memories were traumatic in the slightest. They were just little forgettable things to an adult that were new and unusual to me as a toddler.