Ok, so the uncle was next door and I just read a post a couple of threads back saying he was working on the neighbor's roof? Was the neighbor home at the time?? Because when someone is working on your roof you hear their constant foot steps as they work up there. I'd think if he was working on the neighbor's home they'd know if he left for any significant period of time.
Also? While the green van could be a red herring. If I learned someone next door disappeared and I was outside I'd also think back to any car I saw come by that I was not familiar with. It's possible someone saw that car and is bringing it up, the car was actually there, but not related to her disappearance at all.
I'd just really like to know if the neighbor was home while uncle was working on it though.