Bloodghast's landfall ability triggers only if it's already in your graveyard at the time a land enters under your control
If this causes the number of historic cards in your graveyard to change (probably because you are casting The Capitoline Triad from your graveyard), that new number will be used to determine the cost reduction
The chance at getting 5 legendaries in a pack is astronomically stacked against you, but you still have that what if feeling
Once the card is out of print it may go up in price, but its not guaranteed. Jason A., a collector from East Tennessee who declined to give his last name, compared it to the stock market: You can take a bet on a cards value
That seems really good in the right shell
Each tier has a smaller card pool and is progressively rarer, with immersive (Three-Star), Shiny Two, and Crown rarities being the most elusive