The in-game trades don't have story. They were replacements for the Red/Green trades so that players would know the four trade evolutions (as they both involve players trading one trade evo mon for another). I played Green, Blue and Yellow in both languages next to each other last year and the most significant change I spotted is the SS Anne chef's meal was changed between Green and Blue.
Maybe restore the intended line for the Cinnebar Raichu trade from Green. (that mistakenly says Raichu can evolve, something we only learned this year was a deleted mon in reality)
Possibly the Cerulean police was a bit more sympathetic. In Yellow the line in Sabrina's Gym was changed because of the Ghost vs. Psychic bug, and the localization made a mistake in Yellow about where Copycat lives (a line in the Celadon Dept Store).