Cold Steel: D on't people who think they're anointed have to tell the elders of their status?
No. They announce their status by eating crackers and sipping wine at the funnest holiday the dubs have, the annual "Memorial" of the Last Supper.
I don't know how people announce these things to the elders, nor what happens if the elders don't agree.
If a dub claims to be anointed, the elders cannot agree or disagree. It's assumed the dub is what he says he is.
Which is more prestigious? Being an elder or being a member of the heavenly class?
If the dub is male but not an elder, the elder still has more status. If the dub is male AND an elder, he's golden. If the dub is female, there is almost no pestige. In fact, she is more closely scrutinized than the other dubs in her KH to make sure she's behaving appropriately ala dub standards.
Are there cases where someone declares and then is badmouthed by members in the congregation?
Not in my KH. Although one of the "anointed" sisters once invited me to her house for drinks and proceeded to viciously gossip about everybody else in the congregation. Quite an eye-opener about the sanctity of the "anointed class."
I understand declaring when you're not really a member of that class is a serious sin. If you do everything else right, but are wrong about that, would Jehovah forgive you? Or would you forfeit your resurrection?
If the dub falsely claims to be anointed, dub doctrine dictates that the dub will have an eternal dirt nap when he/she dies. But the means by which a dub becomes "anointed" are so nebulous, there's almost no reason to falsify their claim. If the dub feels especially content after a large dinner, that could be taken as a sign by the dub.
Finally, after becoming a Jehovah's Witness, how long does it take before you're informed that you are of that class? Are we talking days, months, or years?
Assuming Jehovah does the informing by means only dubs could invent, it could be any time after baptism. Underage baptized dubs might be questioned about their claim; but, otherwise, all dubs are potential "anointees."