Encoding Cipher onto a creature does not trigger Heroic. Hidden Strings can trigger Heroic once per time its cast (including copies), but Hands of Binding will never trigger Heroic. Also, clever idea with Nivmagus Elemental, +1

I'm looking at different ways to give my stuff doublestrike to abuse Hidden Strings and Hands of Binding ,

Knowing that Fireshrieker is a viable option, what are your thoughts on what could to the trick in W/U without adding another color.

The only other options in Standard are Fencing Ace and Ajani, Caller of the Pride .

You wanna do something sneaky and fun? Ethereal Armor and Hopeful Eidolon or other one drop creature/enchantments.

I could be wrong, but I was just reading in a Born of the Gods review that enchantment creatures are still counted as enchantments when they are creatures. Slap the armor on one guy and suddenly all those 1 drop eidolons are doing double duty. Wanna do something real sneaky and fun? Put TWO Ethereal armors on the same guy hahaha. But make sure and keep a Gods Willing or Mizzium Skin in your hand to save him haha.

and instead of Wingsteed Rider maybe consider one more Phalanx Leader and a couple Cavalry Pegasus