Quick answer to only a part of your original question. Not appropriate on APUG to go on at length about scanning etc, but this might help you.
I always found scanning c41 a nightmare to colour match, until I discovered this Plug-in, recommended on Large Format Forum:
I use it for scanning Kodak Portra and it really is superb. Your c41 scanning issues might not be a problem with your scanner, rather colour matching?
Hope this helps,