Mulligan anything for elementals, since land requirements are the only negative side of this deck.
This deck allows to take control of the board and easily harvest from 3-4 faeria wells thanks to all the jump and charge2/flying creatures. Don't hesitate to use your removals in early turns if it means keeping control over the wells. If you manage to do so and reach late game in good condition the win is secured due to incredibly good cards like twinsoul spirit, fugoro and even manta rider that can be spammed thanks to your auroras creations.
The matchups are always favorable unless against yrush, which you can beat even by playing offensive if you have 1-2 manta riders and enough soul drains, but usually it's a quite bad matchup. Yellow tempo can be annoying sometimes since it is usually faster and more consistent at board control but I'd say it's a 55%/45% matchup.
Anyway the win rate is really high and reaching god rank will be easy :)
Try it out and have fun!