My quick two bits on this: 10 (sorry terrible joke).
To expand slightly, here goes:
1- A static library can depend on another static library, nothing or even a dynamic library: in the first two instances all the code for the new static library would be incorporated in the new SLL (Static Link Library), however, the 3rd option, depending on evironment could lead to the SLL having one of the following outcomes,
- it would contain static versions of the code required by it gathered from the DLL (Dynamic Link Library)
- or, much more horribly, you would have a static library that when included in a project would cause the requirement of shipping with a DLL , breaking the whole point of static linking.
So in short yep, you can link a static library to a static library
2- if lib1 and lib2 are both static, and lib1 has been linked with lib2, then all the functionality of lib2 would be available within lib1 without the need to include lib2 as lib2 would be statically linked within lib1 (think russian dolls, with lib2 being the smaller).
In the scenario you describe there must be discrete functionality available in each of the files you are having to include, which is not statically linked, hence the need for multiple files, otherwise you would have a single file to include and you would be fine.
Take the following:
One .h file with references to 6 statically linked libraries: you would need to include 7 files in your project to get full functionality
One SLL which was created from said .h File would require only the new SLL to be included for linking at compilation:
Hope this helps and that I have understood what you were asking.