We’re both on similar missions :’) my Sapphire and Emerald files have both mixed records with each other, and a Ruby save file I no longer have. I just wanted to replace the battery and reset the RTC to battle myself but I saw the same video on the Blastoise rescue!
I’ve done a lot of research since that video because I wanted to dive into the code of the game myself (nowhere near that yet, just about getting started! I haven’t coded anything since MySpace and tumblr layouts) the bulbapedia article mentioned in the video is here:
https://m.bulbapedia.bulbagarden.net/wiki/Save_data_structure_(Generation_III)
The HOF data does have the PID of the pokemon so if the ones you’re looking for have entered the hall of fame then you’re in luck. It won’t tell you too much else about the Pokemon though other than the level/species/OT.