Five Loyalty - Because most decks only interact with burn or swinging into them, the more their initial loyalty is, the better they are at lasting until later in the game
Miracle [cost] (You may cast this card for its Miracle cost when you draw it if it's the first card you drew this turn.) Miracle is a keyword mechanic that allows you to cast certain cards for a much lower cost if they happen to be the first card you draw in a turn and you reveal them immediately
Well, I had the same question until I got a phone call a few weeks ago
The +1 lets you examine the top two of your library and then exile one and draw the other
As a result, The Skullspore Nexus is likely to be able to reduce its own cost down to almost nothing
Every rulebook card can be found in Set, Draft, and Collector Boosters in non-foil as well as traditional foil