BP7: DLL in DOS protected mode program


I have two questions regarding the usage of (Windows-)DLLs in a DOS
protected mode program:

1) Which Windows functions may the DLL use? The docs say, it may only
use functions from the WinAPI unit, but I found that functions from
other Windows-specific units work as well (e.g. AnsiLower from the
unit WinProcs). So, how do I know which functions will work?

2) How do I know which functions are called from within of a DLL, if I
don't have the sources? Ok, I could try it and wait until the program
crashes, but there should be a better solution, shouldn't it? I tried
TDump on a DLL and saw all(?) the imported symbols:

Imported Names Table            offset: 011Eh
    name                               offset
    KERNEL                              0001h
    USER                                0008h
    GDI                                 000Dh

That's nice, but where can I find the _name_ of these functions? If I
had the names of them, I could at least test if they work under DOS
protected mode.