A fot valve is only used on a jet pump. Submersible pumps have an internal or external check valve. If either leaks you lose pressure. If the line of fittings leak, you lose pressure. Neither type pump stops water flowing from through tem backwards.
To pull the drop pipe in the well can take special tools and experience, it depends on what material your drop pipe is made of and how deep it goes and if you have a pitless adapter and the well cap is above ground etc.. If you have a two line deep well jet, the drop pipeS (a pair) can be as long a 180'+/- and heavy. They can be 20' sections of galvanized adn will be 1" and 1.25" diameter wit hcouplers to undo. PVC same thing but the cuplers could be cemented rather than threaded. If coiled PE tubing was used, it's the lightest and used insert/barbed fittings with hose clamps; about the easiest to work with but the longest to deal with.
I don't charge time and materials, so I ask about the well and base the charge based on what I preceive as the difficulty of the job and I don't dig. S oif the casing isn't above ground I withhold my quote until I know what the top of the casing looks like and how deep it is. Buried sanitary seals can difficult to remove.
My advice... if you have that type well (or not) and pull the drop pipe(s), put a pitless adapter and submersible pump in and extend the casing above ground at the same time. Don't call a plumber unless s/he knows wells, look for a pump guy or well driller.
Quality Water Associates