That enchantment was originally part of 1998's Stronghold set and can only be found in The List (a curated list of older cards that no longer appear in Play Boosters nowadays), making it rather hard to acquire unless you pay the circa $4 to buy it on some kind of marketplace
It seems like it just might be fast enough (of course those plays outlined above were of the optimal sort) that it may not need any Kraken Hatchlings, Isleback Spawns, counterspells or the like to help it get there, though you may never end up playing Jace's Ultimate because he'll probably take a lot of beats, but hey, that's almost the same as gaining life, and anyhow, once he's dead, you could very well have drawn into another one, so that works out too
Cards that reduce equip costs to 0
Up until now, the Ally subtype appeared exclusively on cards from the MTG plane Zendikar, and almost all of those are from the original Battle for Zendikar block
Yggdrasil, Rebirth Engine is a fantastic way to recycle your best creatures and get around high casting costs by directly putting the creatures onto the battlefield
Zurgo only prevents sacrificing during the end step, when mobilize would normally get rid of them
