You have to edit in Photoshop, to some extent. Otherwise you will be trusting your scanner beyond its capabilities. Basic cleaning and sharpening are the obvious ones, and using Curves is little different from selecting a paper or filter contrast.
If you take a look at Angus McBean's work, he merged negatives in such clever ways that it must have taken him years to perfect his darkroom techniques - stuff you could now do in two and a half minutes in PS. He was perhaps the ultimate in traditional darkroom photo-manipulation ... but I hate most of his work.
Keep it simple, I'd say, but keep to what you envisaged.