-1 Pyromancer +1 Electrolyze/Thought Scour?
-1 Island +1 Desolate Lighthouse/Moorland Haunt

4 Pyromancer doesn't seem correct, but the deck needs enough creatures to run smoothly.  Unsure if cutting the Pyro for an Electrolyze and not a creature is the right call.

Hibernation, Threads of Disloyalty, Kor Firewalker, Dispel, EE

-1 Stony Silence +1 Kataki

Seeker of the Way
Monastery Mentor
Boros Charm
Celestial Purge
Scouring Sands
Flame Slash
Arc Trail
Dragon's Claw
Mantis Rider
Vendilion Clique
Threads of Disloyalty
Detention Sphere
Molten Rain
Sulfur Elemental
Rending Volley
Monastery Mentor

Answer to Rhino?

Sword of War and Peace/Fire and Ice?  Maybe Feast and Famine?  Powerful with Token sources

All things considered, Remand actually does more than Vapor Snag in terms of tempo.  Sure the one life point loss is nice and the ability to bounce a Snapcaster or Pyromancer to blank an opponent's removal spell is also good, but being able to Remand a Siege Rhino or Karn is considerably more powerful to me.  The only creature that Remand really misses is Siege Rhino.  Drawing a card also puts it ahead by a considerable amount in terms of my perspective on relative power.

-2 Vapor Snag +2 Remand

Damping Matrix or Rending Volley for Twin?  Or is Spellskite, Wear/Tear and Celestial Purge enough?

Aven Mindcensor?  More options vs Tron?  Monastery Mentor seems really strong as a single threat, especially with Prowess to dodge Pyroclasm.  Mantis Rider as well.

Deprive?

Geist is strong vs Control (UWR specifically, falls similarly to any of other other threats in the deck to Inquisition and Thoughtseize vs Esper/Grixis...) by providing a powerful body that can't be hit by removal.  However, it still gets terminated by Anger or a Wrath, but that does force a Wrath effect on a single target if it can resolve.  Considering swapping it out for Monastery Mentor/Mantis Rider/Clique.

Desolate Lighthouse vs Moorland Haunt?  Lighthouse fuels Lavamancer, Haunt provides additional actual threats.

Dispel?
Damping Matrix?  Strong against Twin
Shadow of Doubt

Pillar of Flame vs Finks/Voice decks in board?

I would like to make room for a Rending Volley in the board, but there's not really anything that I can cut.

-1 Young Pyromancer, +1 Vapor Snag?  Snag offers a bit more utility vs the challenging creature decks while also upping the spell count for Delver and the remaining Pyromancers.