A 110-card count job with unique backs need 4 sets of plates (2 for the front and 2 for the back) while common backs will only need 3 plates (2 for the front and 1 for the back)
Take a look at the lists posted here on Moxfield
If that creature's power is 2 or less when it enters the battlefield but becomes greater than 2 after the ability triggers, each opponent will still lose 1 life and you'll still gain 1 life
I have already seen one- or two-ofs in white-based control decks in Modern, Pioneer, Historic, Alchemy, and Standard
This has led to some variation in foil cards over the years, most notably in the sets Future Sight, Lorwyn, and Shadowmoor, which featured darker foils than other sets
To get a Turn 2 Henzie (and therefore be able to Blitz a creature on Turn 3), you have to run around 12-15 mana dorks, and/or cards like Utopia Sprawl and Elvish Spirit Guide/Simian Spirit Guide