I’ve seen you’ve added letters (a) and so on. That is probably the best solution. With HTML what you would do is, you would add that differentiating letter (a) within the HTML code and then add the same letter (a) to the internal link in the HTML, which would all be in the background and then the linked word could still be the same as others but the code would tell it to link to different parts of the document. However, it’s an awful lot of internal links within the HTML and BB code probably just isn’t set up to do that.
It looks good anyway, the way you’ve done it. You’ll be an expert by the end of it. And you’ve organised it incredibly well so the as 5e case gets bigger anyone could just drop in and pick out parts to read.
I think it’s excellent and thank you for doing it for us.