Yes, thanks to everyone who attended and provided tools, parts, advice, enthusiasm and muscle on the job.
I had a leaking axel seal and an odd on off the throttle stutter/thunk that I thought might be a axel going bad causing collaterally the leaking seal. Charlie provided a known good used axle to help. I haven't driven it much since but the leak is gone but there is still a little thump/stutter every so often, it is better so possibly the left axel is bad as well. I think the car may have been in deep water at one point and possibly the axles boots may have let in water.
That shield is on the trunk wall and pretty far from the axle. I noted the rub through but not sure how it happened. The rest of the car looks pretty good underneath, all shields in place. Oddly someone painted the bottom. It's more than just overspray from when the topside was painted a long time ago. Very little corrosion and no real rust except behind some of the engine compartment insulation under the heat grills that let in and trap water.