Games go long enough and spells are explosive enough that the 3/3 isnt nearly as much downside as it would be in a 1v1, 20-life format
This is called The World Rule. World is an obsolete supertype that works a lot like Pokmon's stadium trainer cards and hasnt been printed on new Magic cards since 1996's Visions
Even so, surveilling cards to your Graveyard will not just improve your draws and hands but also enables GY strategies and synergies such as Delve threats, Arclight Phoenix and others
Reveillark's death trigger will activate again, you can repeat the whole loop as many times as you want: use Reveillark to bring Karmic Guide back, use Karmic Guide to bring Reveillark back, sacrifice them both to Phyrexian Altar
The copies will then resolve like normal spells, after players get a chance to cast spells and activate abilities
The rarity of the cards that you get will be as follows: 10 Common Rarity 3 Uncommon Rarity 1 Rare or Mythic (The chance for this Rare/Mythic slot of the Booster Pack to be a Mythic is 1/8) 1 Basic Land The token card will usually represent some kind of token that links to other cards in the set