I just checked your website and the Libre Caslon font seems to be loaded. Can you set the Default Theme Font for headings and tell me how it works, please?
Regarding the gradient color, I can see that you didn’t set the intro class for the first paragraph. You can see how to do this right here: https://wordpress.com/theme/jason/setup on the Setup tab, under the Typography Styles section. This should do the trick.