right click > Trace Bitmap> multicolor (scroll to color in detection mod)

https://designbundles.net/design-school/how-to-convert-a-jpegpng-to-a-vector-in-inkscape

Sorry for being vague, I don't do this often...

Something something.. path...
trace bitmap tool...

Which is probably covered in your links.

Anyway...
You'll likely have to play with whatever levels and clean up manually.
Level filters can be used on individual color channels if I remember right.
Beware the tool not liking super sharp angles too much. Finding the sweet spot between too much smoothing and too much noise is sometimes annoying.
Compression artifacts can cause noise in the path, the cleaner the source the better.

I don't remember the menu, but you can also edit individual points in the generated path if needed.

Anyway, that's what I do to transform a picture into a 2D path to later import in 3D CAD software.

I dont really know how to use Inkspace so my method is probably very roundaboutish but the way I used to do it was:

1.- Use gimp to turn the image into solid colours. IIRC the option is called posterize, I would choose 5 coulours for this Image but you have to experiment whats best.
2.-With the colour selection tool, select one colour and make a new png for only that colour shape.
3.- Do the same for the rest of the colours.
4.- Import one of the colour pngs into inkscape and use the vectorize function, I very rarely needed to do adjustments to it unless the shape was complicated.
5.- Remove the imported png and adjust the colour of your new vector object if needed.
6.- Repeat 4 and 5 for the rest of the pngs on the same inkscape document.
7.- Align objects if needed and save to svg.

Hope I explained it in an understandable way, if not, feel free to ask.

No tool in Inkscape will get this 100% right without the need to spruce it up afterwards. I would play around with the trace tool until I get a preview result that gets everything right, i.e. the edges - don't worry about the colors because they are easier to fix later - except the gradient in the ear and on the chest. And then you go in afterwards and manually fix/draw over those sections until they look like the bitmap.

I'm not anywhere near my computer so I can't give you more specific instructions.

I was curious about the terminal command in the first link you posted. It turned it into an svg, but it didn't really make an svg. I was curious if it was going to be able to automate it a bit. I guess it gets all the colours in there though. You could probably do that outline tracing after that.

I'm curious about this too. Making SVGs is something I feel like I'd like but haven't touched.