On OSX Jaikoz updates iTunes with changes by default although you can modify the settings in Prerences:Save:iTunes. Changes to files under iTunes control have their metadata updated , and files not yet under control are added to iTunes.
If renaming files in Jaikoz I would recommend within iTunes not having iTunes configured to Advanced:Keep iTunes Media Organized. Also be aware that by default when new files are added to iTunes then iTunes make a copy, I would disable this option as well.
Regarding Traktor do you mean this software http://www.native-instruments.com/en/products/traktor/dj-software/traktor-dj/ .Ratings is a complex matter and I’m unclear what you are asking. You can modify ratings in Jaikoz and they are saved in the file, iTunes will ignore the ratings of files already under iTunes control because it stores them in its own internal database, but it will use the original ratings when adding new files to iTunes, but if you are playing songs in Traktor not iTunes then this is irrelevant.
What is relevant is using the mp3 format is that although ratings are stored internally in the file using a number from 0-255 how this number is interpreted between different players is different. That is why you can change how Jaikoz maps the star rating to the internal scale in Preferences:Save:Compatability:Upload and Save Ratings so compatible with. But I do not know what Traktor uses, you’ll have to try it out, but if not using mp3 format than there is no issue.
Hope this helps.