yikes!!! That really sux!
Wd40 is a terrible choice for what you are trying to accomplish. Once the oils evaporate, the substance left over promotes corrosion.
the first thing I would do is tear the engines down and see what you need to replace. Once you have a list, I would go from there. You might consider buying a couple used engines. That would Save a lot of money and time. Make sure you can do a compression check on anything used you might buy. 150 psi or pass.