flexidesign
1 - I updated the file: /components/com_k2/templates/ja_k2filter/category.php to resolve the warning.
2 - In the menu item settings of this page, you've not set to show Extra fields yet. I just updated for you:
3 - It due to Joomla template you're using jb_brilliant which loads custom bootstrap and accidentally, it has style for the input element - the same as in the filter sidebar so the style of template overrides the style of module.
You can override it by this custom CSS into your template:
ul.ja-k2filter li input[type=radio], ul.ja-k2filter li input[type=checkbox] {
position: relative !important;
}
