For adding multiple instance of message block in course page you can edit <your moodle>/blocks/messages/block_messages.php and change / add the below code to true.
function instance_allow_multiple() {
return true;
}
This will allow you to add multiple instance of message block in one page and to change the name of the block you need to change the title in the below code
function init() {
$this->title = get_string('pluginname', 'block_messages');
}
Regards,
Purnendu