If you look close enough you will find many references hidden away
Lands that say they come into play tapped, like Haunted Mire, will still come into play tapped if you search for them with Nature's Lore or Three Wishes
Kiora, Sovereign of the Deep is the natural commander for this deck, letting you combine the might of cards like Arixmethes, Slumbering Isle, Koma, Cosmos Serpent, and Aesi, Tyrant of Gyre Strait under one leader
If the target creature or enchantment is an illegal target as Withering Torment tries to resolve, it won't resolve and none of its effects will happen
Since Mirri, Weatherlight Duelist has first strike, you dont have to worry as much about attacking with it to benefit from its abilities
Its an excellent choice, and you can use it alongside the right selection of lands to ramp out something big as well, which is always a nice bonus