Can I add default values to the fields?
In our development history there were no a lot of issues with requirements to have default values in additional fields.
Usually site editors preview new content before publishing, so if they miss some values – they don’t need them on the page. All you need is to prepare your templates to process empty values correctly.
Default value can be set only for “Select” field type. You can set the first option to be the default one and keep placeholder option blank. In this way browser automatically select the first option by default (this is standard browser behaviour).