Flex pipe exhaust leak issues - diagnosis and cheapest repair

This is more of a helper note in terms of dealing with and diagnosing an exhaust leak, common around the flex pipe assembly in this V6. In the picture, the driver's side (bottom of pic) flex pipe shows burning damage, missing braid cover, and a broken end cap hanging down loose bottom left.

On repair the flex pipe was found to not be leaking, and only the flange to the left of the pic was leaking due to bad bolt and loose flange. Accordingly a great deal of money was saved by only replacing the flange gaskets (CAD $8.44 each) and leaving the flex pipes alone.

Note that if the flex pipe was faulty, the solution was to cut out and weld in a new flex pipe section for the damaged side (< $100 part), NOT replace the entire Mazda part that consists of part #6 in the below shop diagram and apparently costs $1000. To remove that part also involves, as shown in the shop diagram, an SST to remove the hot oxygen sensor, creating more expense and risk.