but I've already come up with nearly the entire cast, not just the main and supporting cast but even the extra NPC's.
As in you've held auditions already, or have people who've played these roles in another project, or simply know who you WOULD cast, given the opportunity? If it's the FF7 fandub I've seen that you were involved in... well, the acting in that is a mixed bag. Some of it is great, some of it is less so.
I do think that ideally it would be best to keep this project completely separate, and with its own auditions. Definitely let the cast of that know about this project and encourage them all to audition, but at the same time, this would give the opportunity to potentially discover someone who may not have been around in 2009 back when that project began. You never know when a hidden gem could blow your minds.
And yes, my reasons are at least in part selfish; I want to audition for Reno, and win or lose the role based purely on talent and because someone else got it for a totally different project
Still, I think my points are valid.
edit:
I can't send PM's yet because I don't think the admins made me an "official member" yet.
There's a five post minimum before PMs are enabled, as a spam combat measure. You should be past that point now.