What's the Jackson deserialization equivalent of @JsonUnwrapped?

You can use @JsonCreator with @JsonProperty for each field:

@JsonCreator
public Parent(@JsonProperty("age") Integer age, @JsonProperty("firstName") String firstName,
        @JsonProperty("lastName") String lastName) {
    this.age = age;
    this.name = new Name(firstName, lastName);
}

Jackson does type checking and unknown field checking for you in this case.

It does work for deserialization as well, although it's not mentioned in the docs explicitly, like you said. See the unit test for deserialization of @JsonUnwrapped here for confirmation - https://github.com/FasterXML/jackson-databind/blob/d2c083a6220f2875c97c29f4823d9818972511dc/src/test/java/com/fasterxml/jackson/databind/struct/TestUnwrapped.java#L138

@JsonUnwrapped works for both serialization and deserialization, you shouldn't need to take any additional steps.