Correcting color cast in scanned old slides

I have a huge amount of old slides, already scanned by an 'Epson Perfection V500 Photo scanner. Lots of these slides (various film emulsions: 'Agfa, Kodak, Fuji) show their age with the typical color cast: magenta, red, blue. What are the best settings and workflow for their adjustments in my version 3.6 of Aperture. By trial and error, as for using the various 'Color' adjustment sliders too, I corrected slide 1 (see images 2-3). Before continuing with slide 4 etc. for better results, I hope for some advise as how to proceed at best. Are Lightroom, Photoshop or other photo editing programs better equipped to this task?

(An additional question about photo's: how to convert a negative to a positive image - see picture 5?)

I run version 10.10.3 OSX Yosemite.