I worked on this a long time ago but forgot to register. I'll send you my save file (100%!). It has an NPC in the trainer house. One way to find the offsets is to search for the team that's in that NPC (for example, look for Garchomp). If you make any progress or manage to fill the trainer house with trainers, please share. Good luck.
POKEMON HG.sav
Can I edit the Hex Mystery Gift Record (export Object KMysteryGift block) using a Pokémon event .wc9 file? I have the Dot Quaxly in the Mystery Gift Record and I compared it with the .wc9 file and they are very similar. I wanted to edit the MG record for shiny Miraidon/Koraidon :).
If you know Hex Editor, you can use the post above. If not, one way is to edit your Pokes with one less affection heart and increase it to 1, 2, 3, or 4 hearts and get a decoration.
Every time I edit my save in the hex editor, I need to put it in pkhex and save it before injecting it into the game. If I don't do this, the save shows as corrupt. Why does this happen? What does pkhex do and can I do it manually? Can I apply it to other games?
I don t know any. Open your save with a hex editor and try to understand how it works. You will need to identify where in the save corresponds to trainer hall.