Yeah, unfortunately .rels don't work like that, you need a specific .rel for each character, you can't just rename it and expect it to work. However, there is a generic Ike .rel that can be modified to work with any character, but to modify it you would have to know how to use hexing. I don't know how to use hexing, so if you want to try that you'll have to ask someone or find out how to use it. I do have some Ike .rels over Dedede, G&W, Mario, and Wario if you want to use them, all you would have to do is to put them in your module folder and rename all the PSA files for the character. However, some of them need codes to keep from crashing, so you'll have to add the codes to your RSBE01.gct.
Here's the link to the generic Ike .rel:
http://forums.kc-mm.com/index.php?topic=14915.msg387442#msg387442Here's the .rels I have:
https://www.dropbox.com/sh/p8xxc3usnj49fa8/htOiPgu9o1I don't mind replacing Wario, but I couldn't get your .rel for Wario to work ... the game freezes. I even added the codes for wario in the gct and everything.
To see if I was doing something wrong I tested on Mario and was able to get it to work.
I wouldn't mind getting rid of Mr Game and Watch, but I can't get the alternate costumes for Cloud with him since G&W only has one pac file for his textures. Is there a way to add more textures for G&W?