An older question, but may give you a direction to consider to figure out what to add into the code generating your XML.
As far as I know, the SQL form field will always return the ID of an article.
So you can get the title, into text and intro image, you can use Joomla's Table class:
$array = ['articleOne', 'articleTwo', 'articleThree', 'articleFour'];
// Loop through each array item
foreach ($array as $value)
$article = Table::...
Most form views in core components have custom Joomla.submitbutton() functions. Standard function does indeed support only adminForm as form ID. Instead you can use Joomla.submitform() and pass your form:
<button class="btn btn-primary" type="button" onclick="Joomla.submitform('controller.send', this.form)" >Send</button>