So as you can see, currently there is a steel pipe in the wall, copper service line going thru it, and concrete in between the copper line and steel pipe
Concrete is corrosive to copper (not to steel), so the cementitious fill between the steel sleeve and the copper pipe probably corroded the copper pipe. Although I would think the steel sleeve would also corrode at the outside end, being exposed to the soil.
If you can clear the steel sleeve, and it's not corroded, then you could reuse it. The question is how to properly fill the annular void between the copper and the steel. If you thoroughly spiral wrapped that portion of the copper pipe with 10 mil PVC tape, then a cementitious fill should be OK. But perhaps someone else has a better idea.
As to the mystery exterior pipe, your best case would be former sewer or downspout pipe now abandoned, but it would be a bit hard to be sure of that. How old is the house?
Cheers, Wayne