Is this add-ons output responsive?
Yes, the Personal Like Statistics Tab supports responsive view.
Does this add-on add database queries?
Only when browsing the personal like stats tab, 2 queries are made.
Is it really not possible to use this add-on with XenForo 1.1?
This add-on can be installed and used with XenForo 1.1 without problems. However you need to modify your templates manually. The modifications can be taken from the XML file of this add-on, if you know what you are doing. Also the conditional for responsive view has to be deleted from this add-ons CSS template.
If you do everything correct, the add-on will work with 1.1 also, however we cannot provide any support for this.
First Aid after any problems:
Q: My forum is broken after installing an addon. What should I do now?
A: Deinstall or deactivate the addon and ask for help. If you cannot reach the XenForo ACP any more, login to your web server and add the following piece of code to library/config.php:
This will disable all addons and enable you to get access to the ACP again where you will be able to deinstall the problematic addon.
$config['enableListeners'] = false;