I think you should take out afl and chaos for a boneyard, and a rain of fire.
Chaos power is nice but it has very little value to field control or card advantage, or synergy with anything besides getting pome points on Oty.
Rain of fire can help keeps swarms down or get some things small enough to be eaten. Also you can get mass kills with it so if you have bone wall, or boneyard out you get insane advantage.... if you have both the computer should quit. lol
Boneyard gives you another way to get creatures to improve and cost lss then toxin, and if you play 2 you dont need firefly queen so you shuld not runout on life quanta as I did when I ran deck like yours.
You MIGHT be able to get away with another Hourglass.