I'd personally be happy with the prospect of signing Zaha. I'm not too fussed about fees, but I'd hope the wages were lower than his supposed contract offer at Palace (which is what makes the whole thing unlikely IMHO).
I was one of those supporting the Wanyama move and I think this could be just as successful. Has great attributes and has really stepped up this year, I believe Poch could improve him further still. Scary pace and decent trickery, started to rekindle his finishing from his early career too. Questions on his vision and final ball but would have plenty of options with Kane, Dele, Son, etc... around. ACN the biggest downside.
I'd also be interested if Poch could experiment with him at RWB if we continue to use 3-4-2-1 often. He could be a better version of Moses.