Ok..let'* clear this up.
You may lose 2 or 3 drops of oil that are on the sender.. the oil should be in the pan and this should be done when the motor isn't running
As for the splash shield..it'* easy and you can't hurt it easily unless it'* -20F and you try using a hammer to remove it. I suggest a trim panel tool or screwdriver and needlenose pliers.
On the pressure sender replacement itself. It'* easy to get at in this position.. tough would be trying to get it from around the transmission if you were under the car. (IMO I rate this the same or easier than changing our rear spark plugs.)