I am planning to purchase DS-7616NI-Q2 NVR and 16 Acusense cameras. Since NVR does not support Acusense, Will all the functions works regarding Acusense including alerts?
That should be fine then, The NVR does not need to support AcuSense to support AcuSense cameras. The main advantage of AcuSense NVRs is that they can bring AcuSense features to non-AcuSense cameras.
The only thing we were worried about was incoming bandwidth support because the Q-series models are more entry-level and so don't support as much incoming bandwidth, this means they can struggle when loaded with too many high-megapixel cameras but as you are sticking with 2MP & 4MP AcuSense cameras there shouldn't be an issue.
If you need a light to come on with an event trigger, we would recommend one of the new Hybrid Light cameras like the DS-2CD2047G2H-LIU 4MP Mini Bullet
The Hybrid light cameras use IR & White Light LEDs, meaning you can choose between IR/B&W at night, White Light/Colour at night, or Hybrid mode where the camera will switch from IR mode to Colour mode when an event is triggered.