(NB: I'm not actually asking for an answer to this specific question, just illustrating how messed-up the questions are becoming, these days.)
The best way to deal with this IMO is to take things step by step. Figure out what each card is at any given moment (name, abilities, types). Find out which things trigger when, exactly (so you don't mix "on-buy" triggers with "on-gain" ones, for example). Make sure you know the timing rules (easier said then done
).
Generally, card wordings refer to the "current state" of a card (itself or another), with minimal exceptions (I mentioned Ritual, Jeebus added Treasure Map).
Triggers conditions are, for various reasons, checked again after one triggered ability of the same exact same conditon has been handled. This may allow things to trigger that couldn't before (the 'classic' example is to reveal Secret Chamber to put a Moat from your deck into your hand, then reveal that Moat, then (optionally) reveal the Secret Chamber again to put the Moat back on top of the deck).
Anything on a trigger that is not the trigger condition is only cheched when it resolved/you choose to resolve it. You can buy/gain an Emporium with 4 Actions in play, but call a Duplicate (putting the Duplicate in play) first (gaining another Emporium) and get the +2VP for each Emporium (because you have 5 Actions cards in play now, including the Duplicate).
With 'morphing' cards (inherited Estates, Band of Misfits, Overlord) the IMO most important thing to know is that the rules consider for on-buy, on-gain, on-trash triggers the state when the card is 'yours', that is after the transition for on-buy and on-gain, while before the transition for on-trash.
What these "corner cases" boil down to is the application of *many* things is a short time frame, so why each detail is not that complicated in itself, it's getting everything right that is the problem.