All memory of past lives is stored in the soul body, which is formless and expandable. We have several bodies and the soul body is the highest.
This is a contradiction. Memory is information, which is form persisting over time. What form do our stored soul-body memories take?
We all have to learn for ourselves, and settle our own karma. Nobody else can make our choices for us.
This seems like a very crude and primitive system. Here in the incarnated world, we learn from the experiences of others.
When I was a pre-teen I read first-person accounts of the experiences of heroin addicts and their families, that were published in the newspaper. Those experiences, conveyed by written words, made me fear addiction and convinced me not to use addictive recreational drugs. This valuable learning clearly did NOT come from the memories of any past lives (which as you point out I have no access to in my present incarnation).
That appears to be more effective than the angels' system, which apparently can only teach me about addiction if I experience it myself. (Will they send me back to "try again" to be a drug addict in my next life?)
Furthermore, education is a progressive process. That's why courses have prerequisites. It's much easier to learn to write if you've already learned to read, because you can read many examples of writing. It's much easier to learn calculus if you've already learned algebra. "Welcome to fifth grade; first thing we'll do is erase all your memories of fourth grade, then start over."
As a teaching and learning process, the system you describe is atrocious.
We are all immortal individuals and continue on into infinity together as one great spiritual family. An immortal spirit can hardly be replaced by reproducing.
That sounds all spiritually sparkly but it doesn't connect to moral behavior very well. Would an immortal spirit living infinitely be much inconvenienced by being murdered, or a few lifetimes of abject slavery? Not a bit; in fact those would be invaluable learning experiences. So go ahead and murder and enslave away...