(Dependency Walker) missing explicit type on function

(Dependency Walker) missing explicit type on function

Apologies in advance for noob mistakes. This is my first question here.
First, some background:
I am trying to create a module for a program using dependency walker to
find C++ functions in a .dll that I don't have the lib or any source code
for. You can also assume that I can't get support from the original
developer. Basically, I checked another file that accesses it to see what
the minimum functions were to get it working. Here is an example of the
undecorated names that are output:
void foo::bar::baz(float)
float foo::bar::qux(void)
foo::bar::bar(void)
class foo::bar & foo::bar::operator=(class foo::bar const &)
The top two functions obviously take float or void and return float or
void. I got a similar function working using something like:
HINSTANCE THEDLL = LoadLibrary("C:\\dllFolder\\theDll.dll");
typedef float (*quxType)(void);
quxType qux = (quxType)GetProcAddress(THEDLL, "quxMangledName");
So those are not a problem.
Now, the third on the list looks like another function that takes void,
but it doesn't have an explicit return type. Does this mean I should just
use an implicit type for it, is it void, or is it not really a function?
If not, what is it?
I have no idea what to do with the fourth one. Is it even possible to
handle without the associated .h file?
I looked around, but I couldn't find any information on what to do when
the function doesn't look like a normal function with an explicit return
type. Despite using basically the same code that I used to get a function
working in a similar .dll, I keep getting an access violation crash when I
try to use function #2 here (I really just need function #2). So I am
guessing that the .dll needs more information or needs something
initialized first, which is why I am interested in the others on the list.
I realize this is a complicated problem, so there probably won't be a
"Right answer" solution to get it working, but if I am making any obvious
mistakes, or if there are any general suggestions for how to attack the
problem (even alternatives to dependency walker), let me know.