OpenCV - undefined symbol: hb_font_funcs_set_variation_glyph_func
you can try conda install -c conda-forge opencv, this one also will install opencv version 3.
For your error, you can fix it by install pango using conda install -c conda-forge pango
I have a working anaconda environment on my ubuntu 17.10 machine and installed opencv3 using conda install -c menpo opencv3
When I try to import cv2 the following error shows up

import cv2
ImportError: /usr/lib/x86_64-linux-gnu/libpangoft2-1.0.so.0: undefined symbol: hb_font_funcs_set_variation_glyph_func