Hi kurufal! Sweet deck, and it's cool to see you thinking ahead about to best fit the new Tamiyo into a deck. It's also quite clever to be using Coax to find the big Eldrazi and cast them for free off Tamiyo. I don't know if I can help much with removal, as Bant is pretty light on it (other than
Declaration in Stone, which you already have). One Thought though is to move the
Eldrazi Displacer into the sideboard and bring in something like
Tireless Tracker (just to dig and be a threat). But that way, if you never find a Tamiyo, your Coax can still find a useful card that you can actually cast. Just a thought.
Good luck!