open to using multiple pieces of software to accomplish this task.
I'm glad you allow this. For me, this combination of software does the job really well: Open Broadcaster Software plus OBS Virtual Cam plus VB Cable.
Except for the audio part, this combination is free, also ok for commercial use. OBS and OBS Virtual Cam are both GPL2 licensed but VB cable has volume licensing for commercial use.
Works with Windows 10 64bit
Yes. That's my setup.
OBS is basically a software for streaming content. It's quite flexible what "content" is. This can be static color with text, your screen, your camera or a combination of all that, and probably more. It seems people use that to publish videos on Twitch (streaming) or maybe record tutorials for Youtube (save as file for later editing).
can create a fake (black screen stream)
That requirement gets a big definitely!
OBS Virtual Cam then does the trick. Instead of streaming, you can turn up to 4 virtual cameras on or off. Instead of streaming to Twitch or saving into a file, you now have 4 additional video devices which you can select in your video conferencing software.
Once you have decided how your screen shall look like, you activate a virtual camera via the tools menu:
If you now connect to a video conferencing system, e.g. online, it will present you a list of cameras which includes the virtual cameras (Screenshot from Firefox):
VB Cable is a set of virtual audio devices. It has an input device, where you stream voice, music or silence to. And it has an output device, which acts similar to a microphone, but instead takes whatever you feed into the before mentioned device.
fake (no sound) virtual microphone.
Since you need silence only, there's nothing to do for you. By default, there will not be anything streamed into the input device, so it's silent.
Again, in Firefox, it looks like this: