Regarding audio from IP cameras, if it’s an absolute must, it can be done at the NVR level with audio out. You could even get cameras with straight audio out which would be easier if the choice is there.
Alternatively, depending on how important the project is, you could utilize a smaller 4 channel nvr with audio out that supports onvif. Essentially it’s own device and now you have rca out which can be inserted into c4 for that particular IP camera.
There are other software methods but those are not cost effective when you take into reliability, time and effort to setup.
Ram
Symmetron