I understand what your trying to change here, but you might have to give a plausible explanation later how Shinji's mother's soul accepted an outsider so easily.

Interesting premise. I'm curious.

Having said that, your word usage could use some tightening up. Wait for weight, their for there, etc.

As a long time reader of fanfictions. I have commented on many writers, mostly about their spelling and grammer. However, your point about Shinji being replaced and not altered has rather intrigued me a bit and I applaud the fact that you ARE writing something different yet, similar to that of the origional.

As for your story, I'm interested in seeing how the other characters relate to this Kanako Harley...please continue...

--Aroha

Why ashes? why not change it to body at another nearby location?
good story otherwise