As for that exchange, I would keep the Lash because that lets you one shot someone for commander damage

Okay. It will definitely be something i try out during the testing phase though. The possible sac triggers make it very tempting.

Indeed, at this point it is just a matter of what do you like in the 99 and how well does it play with the other things you have. I'm sure you will make various tweaks through playtesting, but you have a great base here.

Ashnod's Altar + Nim Deathmantle + Wurmcoil Engine = infinite tokens?Should i include the Wurmcoil Engine?

It is infinite mana and tokens, you are correct.Up to you, you have enough tutors that you don't need to worry about redundancy too badly so it is more a do you want it more than something else you run type thing.

May consider Oversold Cemetery. Patriarch's Bidding Grinning Demon ??

The demon just doesnt fit eithing the decks themes and there arent enough of any one creature type to play Patriarch's Bidding. Im not sure about the Oversold Cemetery. That will be determined through playtesting.

would Smothering Abomination work in this deck?