Yea, deception decks these days are a nightmare. They are going to draw counterfeit at some point. They are going to steal your obelisk at some point. A 2/2 zombie is perfect for umber arrow. etc. It's a shame you ran into so many, or you'd have done much better!

Let's talk Cruel Overseer, though. Not sure he fits in this deck, as a major goal is life steal to keep you high on health. He becomes more like a vanilla 3/4 with a low chance of upside. Cambion, on the other hand, would take advantage of your Firespreader, Chimera, and RoD. Not to mention soul burn.

Which brings me to ask how much mileage you are getting out of ritual? I have a few nether decks like this - they all run soul burn. Even one that tops out with Takhat at 7 mana. Necroscepter and obelisk are begging for that GP.

Overall, nice job!