I agreed with it all until the end.
Karen Servas found the dog. She came off very rational and sane.
Kim MacGregor is the flaky neighbor.
The fact that Laci's car is in the driveway, her purse is in the closet, her jewelry in the box on her dresser makes his 'surprise' at her being gone completely implausible. No smell of baking (good point on her being at home to bake when he called), no mess of cooking preparations.
And he calmy got out pizza, used the washer and took a shower???? He should have thought harder about that on the drive home. Makes no sense at all.
Pinz
I believe you're right that Karen Servas is straight but I'm still wondering why she didn't knock on Laci's door. It's not like it was 2 in the morning and she was 7 months pregnant. Doesn't quite make sense to me.