3. It all depends on the pattern. I look for where the cuts are the most delicate and bunched together. Generally this is towards the middle, but not always. I always want to start with the smallest, most fragile cuts first so I have the rest of the piece to support it. And when moving to the next cut, I always cut the edges along side previously cut areas first. Again for support.
4. No, I've never disconnected the blade from both ends. I now have a saw that lifts out of the way, but for 15 or so years I didn't. I was always able to flex the top of the blade get it through the holes. However, you do have to be careful to not put any permanent bends in the blade. When you can, use a larger drill bit. It's easier to thread the blade through a bigger hole. It does take practice to get good a threading the blade with the upper arm in the way, but you will get better at it.