Yes Fireball is probably now incompatible with Creator, since it's been a year or two since they forked it (privately) and worked on it as closed-source project.
Here's a statement from walzer (founder of Chukong, I believe, not of cocos2d-x) basically saying it won't be opened. You could PM him or @ liink him here if you want to ask for him to reconsider. I'm not sure how they make money on it? Maybe they sell services to fix bugs or add features based on those willing to pay? Maybe they sell add-on plugins?
CocosBuilder worked just fine 5 years ago (it still works if you have the right version).
SpriteBuilderX is trying to improve upon it today and should be used unless you had old .ccb files.
We also use Tiled, Spine, and non-open: TexturePacker, LevelHelper, Physics Designer, Photoshop, etc.
We also use in-game editor tools to manipulate our game as well.
We've also added our own custom code for "real" hot-loading, not the fake "hot-restarting" that Creator has, even while using c++, such that we can see immediately the results of editing any of our assets: Textures, Shaders, CocosBuilder scenes, JSON/PLIST/misc text formatted files we've written by hand or from other tools.
/rant - sorry - I'm also sad that they've "wasted" so much time, though it's their time and their choice, on multiple failed editors and projects instead of refactoring the core engine :-[
p.s. the irony that we keep our custom code internal to ourselves is not lost on me, heh