I've downloaded several character editors with the goal of changing my characters' names. In the first one I tried, I changed the characters' names and saved my changes, then closed the program. However, the changes did not appear when I loaded that save file. But when I tried to use a different character editor, I opened it to find the characters had their new names.

In short: the desired changes appear in character editors, but not in the game. Can anyone help me with this?

I am having similar issues. Though I'm trying to cheat my way though MM7 for my second play through...

I can load a saved game and make changes with the editor but the changes don't take effect in game.

Are you running both the editor and the game as an admin (Right click --> Run as Administrator) ? Sounds like a write permissions problem. If your save games "disappear" after running as admin. Don't worry they are still there in the virtual store folder.