Hi,
that’s a good start already. Another plugin that seems to cause trouble is the Shareaholic plugin.
To find out which plugin is responsible for loading the old jQuery library from the Google CDN, I recommend to deactivate all plugins one by one and then check when the line
<script type='text/javascript' src='https://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js?ver=3.4.2'></script>
in the page source disappears or changes.
This might also be caused by your theme, so if no plugin is responsible, try switching to the WP default theme.
Finally, the Google Analytics code that likely have added to the “footer.php” has one wrapping of <script>
and </script>
too much.
Regards,
Tobias