Can a user release a custom of an official ubi dlc? 

no, rules are meant to be read.

Yes, I agree. I believe that you're referring to cf's rules. I'll try to present the inquiry in a different way. Wwise eula states that any project created with their software must be shared across all available outlets, which, in the case of custom rs charts, is cf. The song creator toolkit seems to only accept Wwise. I see no point in sharing official ubi dlc. I also see no point in playing the incorrect notation they placed within the dlc's I purchased. I've spoken with ubi on several occasions about this selling of incorrect tablature. Their advice was to not play the dlc I purchased, and no refunds would be granted for any rs dlc. I just want these charts to be created with the correct notation. This seems like an improbable task... Is there any other means of using the song creator toolkit, without the use of Wwise software? To avoid breaching the Wwise eula. Thanks.

No cause wwise is what RS use and only them offer the tools to convert the audio to the appropriate proprietary format as far as i'm aware.

 

Note that if breaching EULA is a concern to you, using CDLC is already a EULA breach of Rocksmith EULA but EULA are not really unforceable in any country as far as i'm aware anyway so i wouldn't necessarily over think this.

I didn't know any of that information. Yeah, I'm notorious for over thinking, as you can see, lol. Thanks a lot and have a nice day! :)