Just set #tab-additional_information and #tab-reviews to display:none; and got that fixed, for some reason I thought I tried this and failed but I guess it really was that easy haha
As for the button, I have removed the following two lines of code from add-to-cart-variation.js and still getting the same issue
$single_variation_wrap.slideDown('200').trigger( 'show_variation', [ variation ] );
$variation_form.find('.single_variation_wrap').slideUp('200');