Still, though. Once the chain gets reorged, which happens usually for 1 block, the transactions of the block that was dumped become unconfirmed and return to the mempool. Now they can get mined within the next blocks. If I was going to receive a lot of money, I'd ask to disable RBF and have at least 1 confirmation. Disabling RBF means you can't (practically) double-spend your unconfirmed transaction.
Not necessary. Disabling RBF does nothing other than preventing another miner from potentially mining a competing transaction by chance. If there is any ill-intent present, then there is no point asking them to disable RBF because they would have gone a little further to try to get their transaction to get double spent. There's this misconception that disabling RBF prevents any easy double spending but that is false; the primary purpose of RBF is to allow users to replace their transaction with another that spends a higher fee and disabling defeats that purposes especially in instances where fees spike were to occur.
The one and only way to be certain is to wait for 3 or more confirmations (if you are that paranoid). Otherwise, there is little to no security benefits. Anyways, stale block candidates are easily detectable with a well-connected node. It isn't a big problem.
That's true. Chain reorgs, as I've said, usually affect the last block. I don't believe it has ever happened for 2 or more.
Record is about 6 in a very specific scenario, IIRC. Otherwise, normal circumstances would be about 1.