I find placing the cast list at the beginning of a book awkward and perhaps an impediment to reading it. However, if it is placed at the end, the reader doesn't see the end notes or have an opportunity to vote. I guess a note could be added to the end of the story suggesting that they will find the voting and end note at the end of the last chapter. Any suggestions?
If it's extensive, just post it as a separate document that you update as you update the story. Anyone interested, will check it out. If it's not extensive, it's unnecessary.
To me, I think the biggest question is whether the book is being posted as it is being written in a serial style or if it is complete when posting starts. If the former, then you pretty much have to have it at the beginning so that it is present during the release.
Second question would be how necessary it is, which comes down to how many important characters there are. If there are a lot of characters to keep track of and there's a reason readers will reasonably forget details, then having it at the beginning is more important. Having it at the end is a useful crutch for people who need it, but won't bother the people who don't.
So, for example, in a harem story where there are a lot of semi-interchangeable characters, having it at the front will definitely help readers keep track of who is who. OTOH, if you can't tell characters apart by their personality and dialogue, do you really care?
The general rule of thumb I'd go by is front is for things that are needed to understand the story, end is for things that some readers may want to reference, but aren't needed.
I'm not recommending either of these approaches but you could register the story as a series with the cast list as a separate Book 1. Alternatively, perhaps you could put a smallish cast list on the cover page.
AJ
register the story as a series with the cast list as a separate Book
I have received a number of valid complaints about a rather large cast of characters, and other info as the First Chapter of several of my stories.
Based upon several Tom Clancy novels, as well as stories by Jay Cantrell and other authors I admire here, I put my Persone Dramatis at the start of my stories.
I now believe that it would be better to convert to a series, and have the "PD" and other information as a perpetual "last book" in a series; with a reference and/or link to it in both the blurb, and perhaps the first chapter of my stories.
I could also add a bibliography, and "Thanks" as well. That way a person who is interested can open in a different page, print out, or whatever, that information. Others may ignore it.
I have been thinking about this for some time, but have not done it yet. I am trying to complete my main story before I post any more chapters. I have several WiP for when I have "writer's block" on my main story; but I won't past any until they are complete.
Some of this comes down to what the story is. If it's one story, self-contained (and however long), and posted all at once, my preference is end notes (likely along with a pointer to it in the Foreword).
However, once you go to serialized posting, that becomes cumbersome and annoying. In that case, 'at the beginning' becomes fairly reasonable. The big 'gotcha' is that a cast list can easily become a huge bundle of spoilers, and - if it's at the start - it's in exactly the wrong place to avoid actually becoming spoilers. New readers need to actively avoid the cast list.
For a multiple-story work, I would strongly suggest a cast list at the end of each story. Thus, the Book 1 cast list, at the end of Book 1, contains spoilers for Book 1, but that's fine. Anyone reading Book 2 can refer back to Book 1's cast list. Changes to characters within Book 2 won't be covered in a cast list until Book 2 completes posting.
If it's necessary to have an 'interim' cast list, it should be posted as a separate 'story' and deleted when a story is completed.
I've been 'working on' cast lists for a long time, but I'm not there yet. So, I have opinions, but not a working model to point to :)