ad 1) No, Only in each addon. But you using Custom CSS and define Fonts globally for HTML atgs, or/and class names. This is more recommended method that remembering each time to set "FONT-02" for H1.
Guide in Helix Ultimate >> https://www.joomshaper.com/documentation/helix-framework/customization-tips#how-to-add-google-fonts-manually
ad 2) Like above or using Typography from Helix, but you have to know also class names used there.
Here is example how I use in my sites
body, p, li, span, strong, ul, ol, #sp-component p, .sppb-addon-text {font-family: FONT-01;}
h1, h2, h3, h4, h5, h2.sppb-addon-title, h3.sppb-addon-title {font-family: FONT-02;}
as you see very basic concept.