I want to say I have a plan, but I'm not really sure. The best I have at the moment is that when the time comes I'll have a general note that goes out to everyone, and then individualized notes for the people closest to me. Everyone will at least get one last message from me, where I try to relay how much I appreciated them and how sorry I am for the person I was and the things I've done.
The money I have will be split as evenly as possible between my siblings, with no involvement from my parents (my mother especially would make it into a whole thing about "earning it"), though I'm not really sure how to make that clear without having a will and not draw attention to my suicidality. As for my possessions, whoever's left in my circle can have whatever they want and argue among themselves for it.
All this being said, I also fully expect to just say "fuck it" and peace out without informing anyone, and let them figure it out. I don't want to hurt people more than I already would be, but at the same time I can't really say I'd care either.