1) I don't really know the answer for sure, I saw that though :http://www.ehe-lab.com/OpenCV_Wrapper.html, I admit I have no idea how openCV compares to Cognex, Keyence, Matrox, Halcon, NI VDM, etc...
2) NI's OCR and pattern matching are far behind the competitors, so if there is a way to integrate something that give better results I am very interested
3) If I can be of any help I'll be glad, I have to say though that I've never coded in any other language than LabVIEW so integrating dll into LabVIEW is not my cup of tea.
Cheers