This is interesting, to me. There was absolutely no way MS could have known that TS' mom would say no to keeping the girls, so was the original plan for Mark to go home with her? And "survive" the attack? Garner some further sympathy and stage the house a little more thoroughly than was agreed upon by he and CWW?
The one fact that sticks out to me (here) is that we know MS was extremely protective of the girls. Taking this fact into account, MS
planned TS's murder, so
I think he would also plan to be with the girls with TS's body was discovered. How disgusting is it that MS told AL that he was thinking "we should all go, since we're all here at the airport"? MS never considered leaving with TS, IMO, because he wanted to be in control of the girls the second TS was out of the picture. He wanted to control how the girls would hear the news.
Based on AL's interview, the trip was planned in March/April. IMO, MS was already in the murder planning process by then, and it shows through AL's words. The duration of the Grandma visit (2 weeks) seems a little long (both for Grandma and the girls) especially considering MS and the girls didn't plan to stay with Grandma for even ONE week, once the plan finalized.
I think either:
A. MS knew that TS's mom would be apprehensive about keeping the girls for two weeks and flying back to FL, or
B. TS wanted her mother to fly back with the family on Sunday and stay for a few weeks. MS was not having it, proposed to "surprise" the girls with a two week stay in CT, knowing Grandma wouldn't feel comfortable. This assumption was correct, and of course MS offers to stay with the girls...for 3 extra days.
“
Mark and I want to surprise the girls, and
maybe they’ll stay two weeks with Mimi” and I’m like oh great, these are like the daughters that I never had. I said “Oh my God, it’ll be great we can go get ice cream and we can go do this.” And she goes “um, I’m going to ask mommy to, you know, fly the girls back.”
I could infer a few scenarios, one of which is the idea (girls staying with/flying back with Grandma) was MS's. Two weeks is a long time. I never noticed before, but its possible TS wanted her mother to fly back to FL with the girls and stay for a few weeks (as she usually did). AL references people much older having no problems traveling. Perhaps *this* is why Grandma was like no way, traveling with two little girls alone would be stressful especially after spending two weeks without their parents. It seems like AL was excited to have the girls stay in CT, would be helping out Grandma so I'm assuming the flying back was the stressful part.
Side note: I wonder if TS was planning to have her mother fly back with the girls and stay for a while (two weeks?) during a potential "transition period". Still speculating but perhaps MS knew that TS's mom planning to fly back with the girls, stay for a few weeks = sign that divorce is on the horizon. Maybe TS wanted her mom on site during an emotional/volatile time and this gave MS a deadline to carry out his evil plan. Maybe TS's frustration with her mom was more about her mother's apprehension to fly back with the girls, because the true purpose of 'flying back with the girls' was to be a neutral third party in the house when she told MS to hit the road.