I think I figured it out. After inspecting the tovideodevice.dll with the Dependency Walker utility, one of the calls was to sdl2.dll. Or Simple Direct MediaLayer, https://www.libsdl.org/index.php
I packaged this with my applications and they all work now. A caveat is that I HAD tried this before with MATLAB 2015a and did not appear to fix, but seems OK with 2015b. Seems like the compiler is missing something in its bundling, and had found no documentation on this. Would need to include the library as well if using Coder for the library calls.
Hope this helps others that run across a similar issue.