I've found a "better" source, but it's still far from perfect. In it Hiruko is simply called "leech child" and Awashima, who traditions holds is both an island and a personification, is just called... Apa? I have no idea why that is. There are some further details in the Nihon Shoki which are similar but different, like the two creation myths of Genesis.

This article is a really interesting yet brief summation, if it helps?

I feel really bad for causing all these problems!