Regarding pip: I did exit the last docker and startet a new one with docker run -ti -v C:/Users/neuma/fenics/testdir:/home/fenics quay.io/fenicsproject/stable:latest like before. This time everything was working fine (no problems importing fenics, fenics_adjoint, etc.) and I did not have to pip install anything again.
Regarding the ports: Nice, so is it possible to use the PyCharm IDE from within the docker as well? Would be great to gain some basic functionalities like debugging and code analyzing instead of just running scripts from the power shell.