[Suicide Junkie]

Step 3 and 4 can be simplified by just reducing the spin.

All you really need is enough spin to keep the water from splashing the remnant of ceres, and with a very slow spin rate you minimize the forces on the outside.

Also, you don't need to spin ceres itself.
Try placing solar sails and/or solar powered ion drives around the outside of the coin for nearly free spin-up thrust.
Use a pump to push water up from ceres to near the edge of the coin, so it catches and starts spinning. The angular momentum will be taken from the coin, but the sails and drives will spin it up again over time.

As you continue to pump, it gets easier and easier to move the water, since the gravity of ceres is decreasing.


If you build just a thin strip of the coin first, you can then winch rocks up from either side of Ceres for use in building more parts of the coin. Cheaper than rockets.
You should also be able to pick out elements to fuel a solar powered ion drive. You'd certainly need a lot of them, but ion drives have great specific impulse, and you have lots of time to work on the project.