but what I wanted even more were the buttons.
That is what I meant with my previous post - the button sets are stored in your Aperture library. When you create a new library, you have to do it from a library that has the buttons and "export" a new library, not create it from the file menu:
From my previous post:
To create a new library with exactly the same button sets, I usually simply export a partial library from the library that has the button sets that I want.
For example by selecting a folder in the Library source list and then exporting the folder with "File > Export > Folder as new library". This new library will have exactly the button sets as the parent library.
Then I delete the duplicate images from the new library.