There’s is vlog uploaded on 7th April 2021, called * WE ARE IN UNFINISHED HOUSE TOUR* and she shows Regan in her own room at the front of the house, at 3min mark she says mila and Lincoln are sharing, and then shows her and Kurt sleeping upstairs.
Regan is born in December 2020.
Lincoln is born in August 2018.
Mila is born in September 2016.
The above are rough dates based on vlogs she uploaded celebrating their birthdays.
so when her and Kurt moved upstairs in April 2021, Regan was 4 months old, Lincoln was 2 years 9 months, mila was 4 years 4 months.
So her and Kurt were sleeping upstairs and at the other end of the house of a 4 month old.
keep in mind these are also two idiot parents who have hundreds of thousands of people who know their exact floorplan and house layout and that Regan was in a front bedroom near a main road.