I would suspect that little was gained from the search of the house.
I would add two things...first, two bags were dropped. Some guy walking around with two bags...would have been noticed by folks and already committed by the cops. So I don’t think we are talking about one individual doing the whole thing, more likely to be two guys....each dropping one bag.
Second, they didn’t want massive destruction of buildings (like our Oklahoma City situation). They wanted it to be a personal thing....with people hurt as much as possible. It wasn’t intended to be a TV magnet for gapping holes in a building or a bridge knocked down. They wanted people hurt in a bad way. I’m more likely to think this is a guy with a friend...who both have a pay-back situation in mind.
Have you been to a major race? It's not at all unusual to carry four or five bags at once. One friend grabs the stuff for a group of runners and takes it to the finish line. Your idea sounds nice, but it does not work at a marathon.
On one of the other threads, I saw a couple of pictures of what looked like backpacks.
It’s unlikely much would be found, even if they did it. The terrorists come into the country with a specific purpose, live a disposable life, and disappear.
It would be far more remarkable if they found any signs of permanent intent, like a library book or tv guide.