I think the football pitch buff is for mayors house only, nothing to do with your schools however I have not tested the population buff yet.
I have tested instead the weapons buff which does not work correctly on test, It says it works on all types of weaponsmiths but I think a better description would be works on all sword makers as it does not work on any bow or cannon or arquabus or mortars.
if Hover above my xb maker its called a crossbowsmith so to say the buffs works on all weaponsmiths its either not working properly or bad description from bb