Okay, I'm going to say, I don't think Jack dies in the fire. I think something happens to him at the new fixer-upper house. That would explain the two house numbers. I think they're going to have to move into that house, super-quick, because this house burned down.
If you remember, when the kids are at someone else's house, they have the dog with them, and nobody knows where Kevin is (because he and Sophie went to the party in the woods). They aren't devastated because their dad died, their upset because they lost their house (IMHO--worth what you paid for it!). And it's a "day they'll always remember"--at first, because it's the last Superbowl before the kids leave for college, but later because it's their last night in the house they grew up in.
Funny little story--my DD22 is launched and lives 800 miles away, but I hooked her on this show during one of her home visits (maybe last Christmas? Season 1, for sure). She said she'd catch up on demand, because she's a young adult, that's how they watch TV, right, so I didn't even consider that she'd watch the show when it aired. Last night at 10:02 I get a text: "How much are you going to cry next week?" I replied: "Are you kidding? I was tearing up during the preview!"
