How do I combine the provided CEP codeset with BBrawl's? I'm trying to use the GCT generator at geckocodes.org

I think an older version of CEP oncecame with BBrawl compatibility, or I found a version elsewhere. But, that doesn't do much good for the latest version with a couple extra stages. So, instead I just copy/pasted the existing stages over that were updated.

Also, any chance of Super Smash Land stages being added in the future?

Would it be possible to have "Hyrule Castle Siege - Brawl styled by Hozu with credit to Mewtwo_2000" and "Battlefield N64 (Brawl sized version) by Mewtwo2000" included in the next version?

Or is there some files I can overwrite on my own?

Sorry about that. I updated the OP with a link to a zip file with the correct .rel and the newest version of the stage.
I don't think I can help you with the shaking issue, though.

Thanks for the file update!

I posted a bugfix file, because Great Bay was freezing. Download st_custom0f.rel from the OP.

I never experienced the freezing, but with this new file Great Bay lacks water and the Moon for me. Can you upload the old file so I can restore it?

Also, I'm having camera issues on certain courses. Even courses that aren't part of the pack, although the problem began since I've added it. In certain courses like the screen shakes a little bit (like on the Fire Emblem stage during the transitions), the camera now shakes very intensely.