The Vaseline and rubber aren't going to get along well, all petroleum products ruin rubber. Tell your plumber buddy.
I'd replace the sanitary seal with a new one and get all the Vaseline off the casing and drop pipe.
The rubber gasket is between top and bottom pieces of steel. As you tighten the bolts the rubber is squeezed out against the casing and around the drop pipe. I would not rely on the seal holding the pipe, use an elbow to prevent the pipe from being able to slip down through the seal.
Wells are as deep as they have to be to be able to produce enough water for the house.