I never connected the three songs and the lyrics like that from the three separate episodes separated by years. That's pretty damn awesome to realize, so good catch! If you're really into this kinda stuff you should read Unpacking Chuck, written by another Chuckaholic who's just as academic as yourself.
Sure they didn't know how far they'd get but it's clear they carried on the same theme either way.
In any case, I'm pretty sure this wins the award for Longest Post in the /r/chuck subreddit. Congrats!