I seem to remember that before Conquest came out, someone official said that the official procedure was going to be that first you revealed one card, then you revealed the other. But I don't think that ever made it into any published rules, and I'm not sure if it was art first then rules, or rules first then art.
As to your second question, meta is short for "metagame" which is a jargony word meaning "the game above the game" but could just as easily be called the "strategic environment", or the "likely competition".
The word comes from competitive games with tournament play, and I first heard it in Magic the Gathering. There it describes the most popular decks people are likely to play. If your deck can beat the meta, you are in a good position to compete, even if your deck would normally have trouble against a general field.
Conversely, if your deck is powerful in many different matchups against many different styles of deck, but has an unusual and specific weakness to the most popular deck in the format, then your otherwise excellent deck just isn't right for that specific metagame.
I've been criticized by a friend for using the word, so I've been trying to use it less, but sometimes I just want a succinct description that means "the overall population of spellbook strategies that I'm likely to encounter in competitive play at this time."
To give you a practical example, at the moment, the meta is filled with Wizards and not a lot of Priestesses. Newer players always seem drawn to Beastmaster, but your most dangerous opponents will likely have Wizard's Tower, so when designing your book, consider attackers with high piercing and how to deal with high channeling, and (for now) don't worry too much about getting swarmed as long as you have a good range 2 attacker to pick off any weenie strategies.
