This was also a NASA launch, so they probably provided additional cameras and/or stuff like that, like they did with CRS8's chase plane (the first successful landing on the ship, the plane circling the boat was provided by NASA since that too was a ISS mission)

I am guessing that NASA (or more likely the USAF who owns the range) has a lot of the cameras on the launch complex, but not at the landing complex. You can see this on NASA TV which runs a different camera angle during launch, and immediately follows the launch broadcast with a series of replays from a bunch of different camera (running each camera's footage straight). However, during the landing, NASA TV just re-ran SpaceX's content (complete with overlays) and the landing replay was just a single camera shot from the same ground camera.

(However, I totally believe that the tracking camera during the re-entry burn was a NASA/USAF asset).

Given that the launch complex had/has a lot of existing infrastructure predating SpaceX and the landing complex was bulldozed to basically a giant concrete pad and a fire suppression system, that's not out of the question.