Regarding the POI walk/gait in the video. A few things to consider. They are walking with their hands in the pockets of the jacket/hoodie (which will effect your walk to more of a waddle) and the street seems in poor shape with snow --so deliberate footing on unsteady ground. They are also hunched over a bit in the hoodie. Unfortunately really undistinguished video.
During the Brown University shooter (were we to witnessed the inadequacy of surveillance) some sleuths ran computer gait analysis.
Also this is just a POI, given the dearth of info this quite possibly could not be the killer of course, but a person that my have been in the area and viewed as a potential witness. When I lived in a major city we'd see dudes like this walking around all the time in the winter, and at all hours. There is nothing from the poor quality of this particular video that stands out to me.
I do believe indicators at the crime scene and forensics may help. How chaotic was the crime scene? We don't know. Was it clinical and professional or anything at all disturbed or sign attempted theft? We don't know other than what the BIL stated, which is not concrete. Police should also know when the electric lock on the door was opened (it's not a keypad from what I saw but a fob style.perhaps remote operated linked to an alarm), if it was unlocked, if there was an alarm any keypad activity there, of course any ring cam footage (front door was equipped). Of course there's the 4 year old and what she may have heard, though tragically this is very tough territory and I feel they may have been tucked away and witnessed nothing. But, the actual inside of the crime scene that we know nothing about and other incidentals are now crucial in such a murder without apparent typical motives/mechanisms.