i'm in your conscience
Trading the Raikou over isn't going to make it spawn. I'm pretty sure it automatically starts roaming after you get the National Dex, so that's the trigger. And only one will show up. Trading in a Raikou isn't going to make a bunch appear. It's just one per file, and even then, if you find it and it Roars you away, it's glitched you out of being able to obtain it. I'm not sure about it showing up in your Pokedex location if you trade one over though. Not really worth all the effort though. I think you'd be better off trying to get a good nature Raikou from HGSS.