Hmm, it looks like you set up a font mapping entry for the Material Design Icons font, but didn't map it to anything. Does removing that font mapping entry do the trick to allow those Material Design Icons to render correctly instead of as boxes?
Regarding the console error, it looks like you may have put a .js link instead of a .css link in the web fonts tab for your Font Awesome font. Which version of Font Awesome are you currently using in your file? Is it 4.7? If so, and if your current fonts aren't working, then please try using the assets from the link below to ensure that you have matching versions of the widget library, font file, and CSS link:
If the issue is urgent then please feel free to email email@example.com along with your .rp file, your CSS links, the widget libraries you're using, and your current font files so that we can take a look!