these three places use a static font, i make sure to add a setting for next version if you want to manually change it in html templates
open Core > global > global > includeCSS
the last line which is Marcellus google fonts, you can replace with another font.
as for the quick links, its just for links and the sample provided in the field, you cant just place any html and hope everything to work same, however, it should work if you do not remove class names or placing your donate link outside of the links list