Wow, that is amazing, thank you so much! Any idea what could have caused the issue? It was the first time I had booted Diamond in a long time and I was transferring from Ruby using a DS lite and so it's possible it didn't like one of the mons I transferred (nothing hacked or unusual though), but since I didn't actually load my save file before transferring from gen 3 I have no idea if it was already having issues before I started that process.
And then is my best bet at this point to just restart a new save and then inject these mons into that file? Sorry for the dumb question lol