How can I separately edit audio & video data?

[NorseMN]

I'd like to be able to separately copy the audio file and the video data file of an existing CDG, then edit either file and recombine them. ( I have both Microstudio and Hoster, but don't see a way to do this. )

Reason:
I occasionaly come accross Karaoke disks that have an error in the text or omit an audio component from the song that I'd like to add. In the most extreme case, I might want to add my own harmony track to a song that is created as a duet. Then I could sing a duet with myself.

Issue 1:
It's easy to get an audio-only file from a CDG disk. It seems that if I had it in a WAV+G format, Mircostudio could read the pair of files and save them as a BIN file. I have several options for editing audio files, but, I don't see how convert a BIN file from a CDG into a WAV+G file set.

Am I missing something?

Issue 2:
I have found a few software applications that generate the words for a CDG file, but only in a very limited manner. Typically, the words are provided by a text file and the timing is all done mannually, by a process that is very tedious and error prone. It is very difficult to avoid timing issues that cause problems on some players. Apparently, this is because the underlying instructions that are generated are created in an inefficient manner. Another limitation of with these programs is that they allow ( at most ) 2 image files and then only at the start or end of the song. I understand that modern CDG disks rarely, if ever, use graphic images anymore, but the old DK Karaoke disks do it, so it must be possible.

What I'd like, is to edit the text file that already exists. That way, I only have to correct an offending word or two and possibly make some minor timing adjustments. Again, it seems that a WAV+G file set might be a good starting point.

Is any software available that can edit the video data file from a WAV+G file set?
Is this possible by some other method?
What tools do I need?

Issue 3:
Are there legal implications to doing this?
If so, is that why I can't find the tools to do it?

Thanks,
NorseMN