Ok, you asked many questions...lets start at the top. First, believe it or not, the generator is made to come out of the top, you need to remove the what looks like a motor mount, and a few other brackets, push the engine forward, and out it comes. The seat snapping, you need a seat frame, and if i remember correctly, the focus's never had seat mounted airbags, the yellow wiring is for the seatbelt pretensioner, which is also an explosive charge. At work, we never disarm them, just unplug and replace/remove the seat. But if you worry, disconnect the battery, turn the key to on, then back to off, and wait a few minutes.