I've spent hours figuring this house layout out. For starters, this is in no way a 'split level'. The main floor is an open concept ranch. It sits on a modified walk out style basement foundation. Knowing where the kitchen and Jayme's rooms are located, and the size of the house, I don't believe the basement stairs are located in the kitchen. In the rear of the house, between Jayme's room and the bathroom, there is likely an alcove which would align with stairs going down the wall between the garage and basement. I've been in homes with this layout, so it is possible.
I thought no way split level, but the definitions I posted include a house like their house so I thought a definitiion would be helpful so people are on the same page.