If we were to eliminate Wastes in any form, how would we be able to convert the waste into dollar value in order to convince a Bank to start adopting Lean?

The calculation you’re looking for is COPQ or Cost of Poor Quality. The idea is to calculate the labor hours saved by removing waste and then multiply them by the average loaded salary of the process participants impacted. In the case where Defects cause the process to “scrap” products, you can calculate the lost value…