Firstly, if you send an image to the Forum
Gallery titled something like 'advice required about sharpening' then show it here as an example I can't see why it wouldn't be acceptable.
Secondly, if the problem is caused by sharpening, have you tried a bit of Threshold? Say, Amount 100; Radius 1; Threshold 1. Alternatively drop the radius to 0.5 and see if that helps.
If it is the background getting pixelated before the main image is sharp, this is what I frequent do. Draw a selection around the main subject (freehand selection tool), you don't have to be exact as long as you are just outside of the required area. Feather the selection (about 5 pixels) and use 1 level of Threshold with the Unsharp Mask settings.
But I think a lot of your problems are coming from the scanner settings not being absolutely correct. Are you using the 'Professional Mode' ? I found that I had to turn off the automatic continuous exposure correcting mode and do manual adjustments on the preview image. It takes a bit of time but the results are greatly improved.
What resolution are your final resized prints? You should be able to end up with 8 ins prints at 300 ppi without any problems.
It may be worth getting a few prints produced professionally to see if that makes a great difference. If so, you can then start working backwards to try to find out where you are going wrong. While you won't get full professional quality you should be able to get acceptable results with that equipment.