Hi Rikki,
The 7k will work with any software able to choose audio and midi input and output options since you have panasonic usb audio and midi drivers avialable in windows. The Technics software is only a free basic kit to get people started who have no suitable software. You have two independent 16 channel midi drivers to take advantage of the 128 polyphony – see page 48 since frankly, general midi is so backward compared to what is possible from modern keyboards it is getting to the point where it is not worth bothering with except as a means of universal transfer.
On occasion where I want a specific effect I multitrack audio into Sonar (or Powertracks or whatever you like) by just recording the bass into one audio track, then the drums into another, and the rest (or part) of the accompaniment into another, applying software effects, then mixing to a final track. I may not even use a 7k voice but trigger a streaming sample from the hard drive. However there are so many effects and voices available in the 7k that this level of effort is not normally required since so much can be achieved well with the built in palette.

Your example is precisely what I described above. You may wish the vocal track separate for some reason. Record the backing into two audio tracks, then record the vocal in another audio track and edit mistakes and mix later, or save just the vocal track to SD and accompany it with the sequencer or by playing live as many have seen in Technics roadshows, the combinations are endless and depend entirely on what you want to do and the most efficient workflow to get there. I described one way of recording/monitoring on the 7k rather than a laptop if your laptop has poor mic inputs, which can be a problem on many basic pcs and laptops etc. Using the 7k audio usb for all the recordings can get round the problem without spending extra money.

Audio can be multitracked in exactly the same way as midi on the pc except that the number of software effects and voices far surpass anything you can remotely achieve with general midi. Midi scores if you want to play a track live or get a quick notation, but there is no reason why you can’t leave a track out of the audio to play live - the book cd score in screen demos are such an example. Even transposing audio while keeping tempo constant, or altering the tempo while maintaining pitch is no longer really a problem within a reasonable range. The only thing that has held audio back is the expense of storing it, but that will recede as hard drive (and SD) prices come down and sizes go up. In a reasonable timescale it will be affordable to have no hardware voices in rom at all, and all samples will be streamed from hard drive to audio at a quantum leap in quality compared to todays keyboards, but that's another story.
Happy Holidays