hi OP
To answer your original question:
The hik NVR would likely support your Hik cameras fine, the dahua and others would have to be configured via onvif. In terms of video stream this should work fine, but motion you may find doesn't unless they have profile-S supported in the cameras. Onvif can be a bit of a lottery on that front and results can vary depending on which firmware is at each end. I ran onvif fine against my DS7608NI-E2 (non POE) with motion working on cameras that had the TTCellMotionEngine (reported via ODM), other cameras with a different motion engine didn't trigger motion on the NVR and if you find this then you'd have to set them to continuous recording as the only real workaround. I've since moved on to generic starvis cameras that support Hik protocol and they work just fine on this NVR.
For apps, yes iVMS4200 for the PC and iVMS4500 for the phone, best to do remote access using VPN connections and not open ports on the router to save grief later if your cameras/NVR get hacked.
edit: should add that the initial onvif cameras did work fine until later releases of hik NVR firmware where motion events stopped registering, so I downgraded firmware on the NVR back to a working release (3.4.62)
