The first step would be to localize the bfa_theme_options.php file, see https://urbangiraffe.com/articles/localizing-wordpress-themes-and-plugins/
The next step would be to translate it into Spanish, see https://urbangiraffe.com/articles/translating-wordpress-themes-and-plugins/
You would have to turn the texts in functions/bfa_theme_options.php from
array( "name" => "Homepage Meta Keywords",
"category" => "seo",
"id" => $shortname."_homepage_meta_keywords",
"std" => "",
"type" => "textarea-large",
"escape" => "yes",
"info" => "Type 5-30 words or phrases, separated by comma. Will be used as the Meta Keywords for (only)
the homepage. If left blank, no Meta Keywords will be added to the homepage.<br /><br />HTML: No<br />
Single and double quotes: Technically, Yes, but search engines might object to it. Probably better to avoid
quotes here."),
to
array( "name" => __("Homepage Meta Keywords","atahualpa")),
"category" => "seo",
"id" => $shortname."_homepage_meta_keywords",
"std" => "",
"type" => "textarea-large",
"escape" => "yes",
"info" => __("Type 5-30 words or phrases, separated by comma. Will be used as the Meta Keywords for (only)
the homepage. If left blank, no Meta Keywords will be added to the homepage.<br /><br />HTML: No<br />
Single and double quotes: Technically, Yes, but search engines might object to it. Probably better to avoid
quotes here.","atahualpa")),
You would not replace the other text including “options” => …. even though that contains some English terms. Or else more had to changed in other theme files as well.
ref:
https://forum.bytesforall.com/showthread.php?t=82&page=5
edit – -seems someone has done it for you
https://www.gremlins.es/download/5/
