Hello,
1) You can replace this button in the file basel/inc/woocommerce.php
function name – basel_quick_shop_btn()
. Sorry but this additional customization is out of support scope.
2) After adding product to the cart from the Quick Shop page is reloaded and it does not work with AJAX.
3) We will implement our Infinite Scroll in the next update and you will not need to use the plugin anymore. The update will be released next week.
Kind Regards
XTemos Studio