If you really want to commit to the Sirens Call and Angels Trumpet idea, you can springboard off the Mandate of Peace idea and just play Peacekeeper and other cards that prevent creatures from attacking
Considering they are incredibly cheap and self-explanatory, theres not much that can be said about Exploration
You could use the Nautilus offensively, enchanting an opponents creature to make it easier to kill
A 0-mana commander helps to balance Akromas mana value of 7, and youre in good colors for angels, auras, equipment, and some of the other keyword soup cards
I think collecting the Pidgeot ex is a good play as they are only going to become more popular with players as new sets are released and new decks come to the fore
1/1 Insect creature for Aatchik, Emerald Radian