Assume there is a thin conducting shell with a fixed point charge in the center, Q. Scattered outside the shell (not on its surface) there are more fixed point charges.
If I would like to know the electric field inside the shell at point P, do I need to know the magnitude of the point charges outside of the shell?
If yes: why are these relevant? Gauss' law says that flux (and electric field) is proportional to only enclosed charge, so a spherical Gaussian surface centered around Q through P would only include the internal point charge.
If no: why can't I draw a spherical Gaussian surface centered around a non-central point charge through P (intersecting the shell) such that the enclosed charge depends also on point charges outside the shell?