It doesn't copy whether that creature is tapped or untapped, whether it has any counters on it or Auras and Equipment attached to it, or any non-copy effects that have changed its power, toughness, types, color, and so on
The easiest way to lose with Gruul Prowess is to run out of cards in hand
Locus of the Roil is probably the best for a typal Elemental deck, having an ETB and a Landfall trigger that relates to Elementals
Best Pump Spell Payoffs Some number of creatures just want to be targeted with pump spells, whether that's Ashroot Animist so it can transfer that pump to other creatures when it attacks, or The Howling Abomination, which deals massive damage when targeted
Drawing cards is fun, so Ill put it in fun