BBM
How do you know he was home that morning?
Gig, I think you are right (again), and your point makes the most sense of
anything we have to go on:
How do we really know, factually, that Hubert Graham (Sara's biological father) was home that morning at the time Sara allegedly left the house to go to her job at Walmart (as reportedly witnessed by Sara's step-mom, Connie Graham)? Hubert could still have been living at the home, but just not physically there at the time Sara left for work. Hubert could have already left the home that morning, ahead of his other family members, to go to work.
I think, Gig, from the initial reports we followed, to the effect that [the usual routine was] "the Grahams left for work together," we were led to believe that Hubert (Dad) was home on the morning that Sara left for work. But it was later reported that
"mom" (Sara's step-mother) was the only one who saw her that morning as she allegedly left the house to go to her job at Walmart.
As you have posted, we don't know who all was living under that roof other than Hubert, Connie, and the missing Sara (Hubert's biological daughter). (IMO) I don't think they were the only individuals residing at the home.
IMO another possible scenario: Hubert could have been in the bathroom at the time Sara allegedly left that morning, and upon emerging, was told by Connie: "Oh, I was just waving to Sara, clad in her Blue Vest, as she backed out of the driveway [in the white Chevy Astro van] enroute to her job at Walmart!" In which case the white Chevy Astro van would not have been in the driveway when "the Grahams (in this scenario, "Grahams" refers to Hubert and Connie Graham) left together" for work on the morning of Sara's disappearance. This supports my opinion that Sara was not in the house that morning, having left the house the night before [after watching TV with Hubert (her Dad)], and never returned. (IMO) Connie Graham (Sara's step-mom) did not see Sara on the morning that Sara was to have reported to her job at Walmart).
Was there someone else living in the home, or visiting the home, that evening whom Sara knew?
IMO another scenario: Dad (Hubert) could have turned in for the night after watching TV (with Sara and another individual). The other person remained, and continued watching TV with Sara. Or, this other individual arrived at the home after Hubert went to bed. At some point, the individual wanted to go to 7-11 to get a snack and Sara agreed to accompany the individual. She left with the individual, who was driving [his] own vehicle, for what Sara thought was a trip to a convenience store (or maybe drive-thru of a fast-food restaurant), and she never made it back to the house.
My theory only. That night the Chevy Astro van was staged in the location it was found the next day, having been reported as a "suspicious" vehicle by a source/individual undisclosed to the public. Cover-up of a crime ensued, leading to Connie Graham being named as a suspect in Sara's disappearance.
All my opinion.