-> ...should I use MFC or not? And why?
Looks like one of your priorities is to make programming as simple as possible. MFC simplifies programming compared to programming using only the Win32 API. On the other hand, MFC does have a learning curve, but once you've mastered some things, others start to become intuitive.
MFC increases the size of your executable and/or the size of the libraries your program must load upon initialization. Most of the time, that's not a big deal, unless you're developing for internet, where people must download your (large) program and/or it's libraries, or if your application must run on PCs with limited memory (which is not much of a problem anymore).
As an alternative, you could divide your application into two parts:
1) Graphic User Interface (GUI), written using Visual Basic
2) Business logic portion (including processing and database interaction), written in C++ as a DLL library.
This could lower your learning curve, since VB GUI programming is much easier than Visual C++ GUI.
Then, you could concentrate on using C++ (with or without MFC) for just the non-GUI buisiness logic.