If your method works for you Good!!! I respect it, but here is some opinions about your process.


BLUR - MEDIAN - UNSHARP

i start with the worst channel which is normally the blue channel.

i select the blue channel and then i select the Guassian Blur at a setting of around 2 to 5 depending how bad the moire effect is. normally around 2 most times.

--------------------------------------------
2 to 5 pixels Gaussian Blur destroy valuable information in your scanned printed image. Because when you blur any RGB channel, you are blurring color and detail together. It destroy moire, but also destroy valuable information.

For example if you have a girl face close-up. Some thin hair is running thru her face and background. When you blur, this thin hair will dissapear.

When you work in Lab, color is separated from detail. There you can work them independently, and you will be preserving detail while bluring color. You can't in RGB mode normally. You can trick it duplicating layer and merging it using layer Luminosity or Color modes.
-------------------------------------------------

then select the median filter at a setting of 1 to 3, 2 is normally okay for most images including digital photos when removing artifacts.

i do this on the red and green channels as well but alot of the time i use smaller settings in the blur and median filters as these channels are not normally as bad, and besides that it is best to keep one channel untouched if you can so that you can keep some of the detail in the edges.

after i have done all 3 channels (if required)
i go back the rgb main image and select the unsharp mask and use a setting of 100 to 300% and a pixel radius of the same as the blur i use. i never use the threshold in these cases.
eg: blur settings = 2 then unsharp setting will be 2. i use unsharp on the whole image most times.
don't go to high as the moire can come back.


-------------------------------------------------

Under not circunstances you should apply Unsharp mask to all Channels at ones. When you apply Unsharp Mask it creates halos, and when applied to colors unwanted colored halos appears. I apply Unsharp Mask to Lightness, or Black and a weak channel in CMYK, in any case Magenta or Cyan. I never apply Unsharp Mask to Yellow. Another way is appliying Unsharp Mask to all channels, then Fade Last Command and selecting Luminosity merging mode. This way you only apply Unsharp Mask to Lightness even if image is not in Lab Mode. It let you apply heavy Unsharp Mask without compromising over sharping.

Another situation is that printed images are already to sharp, that is why you scan them at 1200 ppi. It soft the image. Of course with your method you need to Unsharp, because bluring destroy details. As you said, you can't sharp it much, because moire will comeback. Also, Unsharp Mask will not bring back details as thin hair.

------------------------------------------------

Hope it helps.

Regards