I pull the pins and let them drop to the ground then move them up 2-3 holes. That way they start out pretty close to level. If you are on a slope and the bow needs to go down, I might do 5-6 holes.
Yes, lock the wheels down as soon as you are in the spot you want.
Rear stabilizers don't mess with until the truck is disconnected and out of the way. If you need to lift the front and they are already down, you can over stress them.
Also, we disconnect the cables same time as the tailgate goes down. With the wheels chocked, no harm in disconnecting.