Hi James, Re, injection pump possibly leaking, the seal was about $10.00 but the pump has to be removed and it can be replaced by someone that is good with wrenches but if it is leaking around throttle control lever then requires pump shop attention.
To prevent front seal leaking, add Diesel fuel conditioner or a couple of tablespoons of 2 cycle motor oil every time you add Diesel fuel.
Re front end loader, yes it should lift round bales, may have to add weight to rear of tractor if the rear tires are not fluid filled. If the loader has double acting cylinders it should easily lift the front end of tractor of the ground.
As per price, it depends on your area.