Kaphotics

A hex editor like HxD can be used to truncate the file back to a size that the program would recognize. It should show a size of 0x?0000 on the left.

Probably wants the save file to be exactly 128KB, no emulator-specific footer.

https://projectpokemon.org/home/forums/topic/65279-pkhex-240603/#comment-290217

Does an unedited save file (from the emulator) have valid checksums, via the SAV tab? If PKHeX remembers your changes, and the emulator reversed it, then that's not an issue with PKHeX. The emulator has to import your edited save file, oftentimes it will ignore it / keep it cached internally with a RAM snapshot for faster resuming.

If reopening the edited save in PKHeX shows your changes, then data doesn't magically revert. I don't know how every single emulator works. If you're not importing the edited save, then it won't use the updated data.

Totally would help if you included your discord information.

Don't look for FRIENDS in the tiny rooms. If the ROM hack is glitched and gives no encounters for that room, then just play on an unmodified copy of the game to obtain them, as this hack has not been updated in 10+ years.

A-Save is a separate program you can download. Without seeing your save file (via upload), can't know for sure. Again, if multiple editors reject it, then it likely isn't a valid dump.

In the unmodified game, the forms you mentioned spawn in different rooms. Could it be you're not looking in the right map?

The Block Editor allows for changing tons of flags, but it is no replacement for regular gameplay progression.

Check if they are indeed valid backups of your save file, and of the standard format that isn't compressed in any way. Try checking other save editors like A-Save; if it doesn't work in multiple editors, then it's likely your save file being bad.

No. Nothing of the sort exists for prior games either.

Bulbapedia has species specific pages with trivia sections.

why not just use a save file editor like PKHeX and limit yourself to only add/change what you feel is right?