FaceGen has an SDK which can be used to put the morph capabilities into your software application. This is what Curious Labs would have done. There is also a customizer which can be used to fit your own mesh to accept FaceGen morphs, along with either the FaceGen modeler or the SDK. Though it is pricy for an individual, it isn't that expensive for a company (IMO). But there is a lincense fee of $995 if you wish to use the customized mesh in your application (or sell morphs, from my understanding if I read the license correctly).

I have both FaceGen Modeler and the Customizer. It does a very good job. The attached image is a conversion of a friend's photo (original top left) to the DAZ David model using FaceGen and the Customizer. It isn't perfect as I did not take the time to fit the David mesh as close to the FaceGen mask as I should have, but the resemblance is definitely there.