1. I pull it from the top. You can go either way, I'm sure if you had a lift it would be a lot easier to do the engine kmember, and raise the car off. its not that big of an engine though and the trans is really small so its easy to get it out. I put the car on stands for about an extra 6-10 inches of clearance but its no big deal. The first time I did it, I had probably 6 or so hours in the tear down and pulling because I had never done any major car stuff before, so I was taking a ton of photos and writing everything down, and putting all the bolts in baggies. If i were to do it again I would only take the upper intake off and the accessories. Lower doen't need to come off. I lifted it by the heads. Two of the bolts on the front for the accessories, in the back I hooked the chains up to the second highest trans bellhousing bolt on either side. Two suggestions, take the crank pulley off if you can, and also remember to remove the radiator. :facepalm:
2. If you do drop it from the bottom, there will be a compression bolt on the shaft. You will have to loosen that, and potentially hit the split with a hammer/screwdriver to break it apart enough to slide loose. Depends how long its been there/rust. I coudln't get mine apart, but then again I didn't really need to go from the bottom. I would just take it out the top.
3. The oil pressure sensor is behind the bracket for the power steering pump. There are two brackets you will see, one is the aluminum bracket that the ps pump is actually connected to, and then there is a black support bracket that goes from the timing cover to two of the ps bracket bolts as a secondary support. Here is where my autometer sender is in the stock location, it just barely fits. It is the big golden super bright circle next to where the PS pump would be.