I just want to clarify that i understand your question. You want to use PyCharm editor and configure it so that it shows you what is available inside the module that has been imported. First I wanted to mention that I was NOT able to configure PyCharm to work, however I went away and did a little research and found that Eclipse with PyDev works.
I installed the IDE including the PyDev module and then created a new project as shown in the next 3 images.
Finally I created a file and entered 2 lines of code
After you enter the dot, the window opens and shows all the functions inside the FreeCAD module.
Is this what you were expecting?
OS: Ubuntu 16.04.1 LTS
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.8066 (Git)
Build type: None
Python version: 2.7.12
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17