Will IOTA smart contracts be able to make calls to external web services or other APIs, or is it too early to tell?
We don't know if there will be something like Smart Contracts. I think you are referring to Q. It's, at the moment, just speculation. Maybe it is something like smart contracts, maybe it isn't. We will see.
IRI supports Extensions. So, theoretical you can implement your own protocol. But you need people who are willing to use this Extension. I also don't know exactly what the Extension interface supports.
/e But I know, for sure, that there is one company working on smart contract on the tangle. So there will be something. But maybe not from the foundation.