I am looking to customize the widgets in my form, to match the font fam

I can see that you're using Droid Serif font. To use that in your sortable list widget, inject this CSS codes within the widget settings.

@import "https://fonts.googleapis.com/css?family=Droid Serif:light,lightitalic,normal,italic,bold,bolditalic";

.connected li, .exclude li, .handles li, .sortable li {

    font-family: Droid Serif, sans-serif;

    color: #000;

    font-size: 14px;

}

Guide: https://www.jotform.com/help/428-How-to-Inject-CSS-Codes-to-Widgets

By the way, checking your live form, it seems the droid font isn't working. It's most probably messed up with the theme's CSS. You might want to inject the following CSS code in your form to correct it.

@import "https://fonts.googleapis.com/css?family=Droid Serif:light,lightitalic,normal,italic,bold,bolditalic";

Guide: http://www.jotform.com/help/117-How-to-Inject-Custom-CSS-Codes