Definitely would not be a bad inclusion. Hopefully I get one in the pre release.

If not you can trade for one!

Prototype Portal+Grindclock Build a Grind clock Army, or use it too create so much more mana with a mana stone.

very nice deck! +1 have you thought on using Lazav, Dimir Mastermind to milk the mill? Bloodchief Ascension//Mindcrank+Dimir Guildmage, Mirko Vosk, Mind Drinker or a Consuming Aberration+Trepanation Blade//Fireshrieker??

This was a Lazav deck before the Commander 2016 gave me access to Silas. All of the cards you mentioned were in the deck back then and it made quite an effective voltron deck (especially with Nighthowler and Bonehoard). I have two other voltron decks, so I wanted to make something different with lots of intricate combos. Those cards are all great suggestions though.

Eater of the Dead works really well with Phenax, might be good if your meta has enough creature decks. :)