What hardware do I need? Multiple audio input devices + BMCC video to Media Express
The page you want to look at is the "Capture and Playback" page of the Blackmagic Products page.  Any device on that page that says "four analog audio inputs" is a good bet.  Media Express does indeed have the ability to record audio and video from an SDI input, and also audio-only from audio-only inputs, giving you a multichannel media file that you can then edit in post.

However...I strongly suspect that the analog inputs of most (if not all) of these devices are line-level and don't supply phantom power.  Depending on what sorts of microphones you have, that could be one or two reasons per channel you will not get a satisfactory result.  Not to worry...you can buy a pair of microphone preamps that take mic-level inputs, possibly provide phantom power (if your mics require it), and deliver line-level signal to your audio inputs.

However, again...many of the products you listed above are OK for use in a post environment where computers (and their noise) can be sequestered from the operator, but they could be a real nuisance when used on location.  Not only is it an ergonomic pain to try to use a computer along side a camera, but when the computer's noise is recorded via the microphones, it adds injury to insult.  There are good reasons that people buy external recording devices and then marry the sound in post: they have mic-level inputs, they support recording multiple inputs to multiple tracks, they usually have long battery life, so can be used on location easily.

If you absolutely must use your computer with your camera, the BMD products will do a good job (provided you have the right signal levels, which you can get with a preamp).  Otherwise, I suggest looking at the ZOOM field recording devices.

Finally, if you plan to use the audio from the BMCC camera, be advised that it's really only good for sync.  The camera's built-in microphone picks up mostly fan noise, and its audio preamps are terrible.  But for scratch audio, it will tell you where the clapper is, and that's a help.  The headphone out jack can feed audio to the ZOOM, and you can plug your headphones into the ZOOM.

If you go with the external recording device, then you pretty much leave behind the world of Media Express.