How to instantiate a blueprint object from a C++ script?

[jwatte]

The call you need is probably UWorld::SpawnActor()
It takes a UClass of the object.
The UClass can come from a configuration property on whatever object is doing the spawning (e g, an Actor or a GameMode or whatever.)
Once you configure the property, it can point at a blueprint class, or whatever other class.
The TSubclassOf<> template is very helpful here:

TSubclassOf