I have about 80 songs created with 2012 - do I need to 'recreate' them with 2017 to reflect any/all RT/Styles upgrades?
I'm not exactly sure what you are asking, but your songs will load and play. When they regenerate they will take advantage of new features that will make them sound better than ever. It's not just improved RealTracks, and new styles to choose from, but also the improved Elastique algorithm and new options in the RealTrack dialog box. You may want to 'redo' them but you don't have to. Were your songs frozen?
No, songs were not frozen - so I would have to load/regenerate all the 2012 songs in order to utilize whatever upgrades have been done since 2012, correct?
Still not sure exactly what you're asking.
How do you presently listen to the 2012 created songs?
Do you presently listen to the songs you created in 2012?
IF you are playing wave, MP3 or WMA or otherwise rendered files of the final mix of the 2012 song projects the new features will have no effect on the rendered files.
IF you want to remix the 2012 song projects by swapping RealTracks, use midi SuperTracks, loops, UserTracks or other instrumentation and audio files added since 2012 you can.
IF you want to remix the 2012 song projects using the same instrumentation available in 2012 you can. The 2017 rendered final mix should sound better that the comparable 2012 rendered final mix because several things have changed. PG Music has updated early RealTracks several times to improve sound quality and performance. The ElasticPro time and pitch shift algorithm both Band-in-a-Box and RealBand use has been significantly improved. Last but not least, your mixing skills have five more years of practical experience.