One question – I have to translate these 3 items’ headers in the header widget – “Our Locations”, “Telephone Number” , “Email Address”. Po/Mo files method doesn’t work as there are no strings with such content in it as in default.po as well as in en.po
The Widgets are created and saved in the database. So, .mo files can’t translate them. .mo file translate only the strings found in the actual .php files. To translate them i suggest you use an actual plugin. Such as WPML.