I'm with you on all that...just exploring what others may think, who hold a little bit tighter to their "knowledge" of what God will and will not do with human "souls".It's a logical speculation, but we don't know that we'd save any (I don't even know if God uses a soul on what He knows will be aborted) _ No one gets an abortion with the idea it will save their baby's soul... We can't speculate on what the not even born's life will eternally end as. It's just a rationale...
And, yes, it is noble to think we could offer our soul for the sake of another...but it doesn't really work that way... God's not a game show host.