Profile Xtra

Upload unzipped plugin directory to the /wp-content/plugins/ directory, or install the plugin through the WordPress plugins screen directly.
Activate the plugin through the 'Plugins' screen in WordPress.

So, this is like a three-in-one cabinet plugin?
Right. Althought imbricated in programming you can distinct three modules or parts: profile image, social contacts, and authors -both the alter author ("alter" means "other", in Latin) and the multiple authors. Please, visit the Options page of the plugin to enable or disable any of this parts...
Can I change font awesome icon used for link to the twitter author's account?
You can change it directly on the style sheet of your theme (the usual way yo do it with Font Awesome). And can change its properties (font-size, color, etc.) as well.
How can use this plugin in a widget?
Well, shortcodes can be used as widgets using the text widget. Just write the shortcode on the text widget content; for example [profilextra]
So, back to the shortcode...
Our shortcode is simple:

To show user name, image, description & link to webpage (in that order):
[profilextra]

but it has many arguments, and arguments has several values, in order to be widely adapted to the users needs or desires. If an argument is not presented, its default values will be considered; the particular shortcodes values have a preference over the general options of the plugin.

Lets see the arguments and its values, and some samples to clarify it:

The argument SHOW determines what to show. Its values are: n, i, d, s
(for name, image, description, and social contacts), or a combination of them, separated by commas. When more than one value is used, it appears in the literal order.

To show only the social contacts of the author:
[profilextra show="s"]
To show the image and then the name of the author:
[profilextra show="i,n"]

To show only 120 words in the description, and ending it with a "...":
[profilextra rmore="120"]
To show only 60 words in the description, and ending it with a "(...)":
[profilextra rmore="60 (...)"]

You can pass a class to the image using the argument ICLASS:

To show the author image with certain style (defined by the class "roundimg"):
[profilextra iclass="roundimg"]

In the Options page of this plugin, you can choose to show the link to the social accounts of the author with the proper name (literally "twitter", for example), or with the regular icon, or with the squared icon. The argument SOCIAL_SHOW is used to overwrite the option of the plugin related to Font Awesome icons. Its values are: name (show only the name), icon (show only the icon), iconr (show only the rounded icon), both (show both, name and icon), or bothr (show both, name and rounded icon).

The argument SOCIAL decides which social account to show. Its values are: w (for website, which is the default value), t (for twitter), f (for facebook), l (for linkedin), g (for google plus), e (for email), or a combination of them, separated by commas. Let's see some examples:

Do not show any social account at all:
[profilextra social=""]
Show rounded icons for website and twitter (in that order):
[profilextra social="w,t" social_show="iconr"]

This plugins shows tha data of the current author, but you can show the data of a given author passing its id with the argument USER_ID.

And, finally, there is an argument to pass a class to the whole: WRAP_CLASS (its default value is 'profilextras').
And what about multiple authors?
You only need to select the various authors of your post; that's all. It works with the same shortcode that you put in your theme for the alternative author or for only one author. If the post have many authors, the shortcode simply iterate from one to the next, until finished.

Each author being iterated is surrounded by a DIV with the class authorxtra; in order to be stylized as you prefer.

Also, you can use the function has_multi_authors in your theme to know if the post have many authors and take decisions in response. For example:

<h3 class="widget-title">
<?php
if (has_multi_authors()) {
_e('About the Authors','olsen-light');
} else {
_e('About the Author','olsen-light');
}
?>
</h3>

And, on the contrary, you can found where current author is part of the multiple authors' team. Use the function posts_where_multi for that. For example, searching on the 'product' post type of woocommerce:

<?php //we are on the author's page sidebar
$theauthor = get_queried_object();
$multi_ids = posts_where_multi($theauthor->ID,'product');
if (count($multi_ids)>0){ ?>
<div class="widget">
<span>I'm also participate as author in</span>
<ul class="products">
<?php foreach ($multi_ids as $multi_id){ ?>
<li><?php echo get_the_title($multi_id);?></li>
<?php } ?>
</ul>
</div>
<?php } ?>