Bats focus on both lifegain and life loss, Mice are Boros-style self-buffing warriors, Rats are a Dimir players dream, and so on
Until then, build out your decks and pop them in a safe container until the Surprise Box comes back in stock
Simon, Wild Magic Sorcerer / Mathise, Surge Channeler You want to build around the group hug nature of forcing your opponent's to draw cards before you jump in with Simon, Wild Magic Sorcerer / Mathise, Surge Channeler
The G / 1 casting cost difference does mean you have to be careful about other colours or colourless land but overall they are both a bit of a pain to cast
Yes, Sapphire Coil can be activated multiple times in a turn, and yes, it's even better in multiples