Hi,

There is no such way to change all loaders in one place because initially, our theme uses pure CSS loader which do not use any additional images or custom font icons in order to improve page speed.

To fix issues you mentioned, please add this code snippet to the Custom CSS area in Theme Settings.

.single-product-page .yith-wcwl-add-to-wishlist a:after {
	width: 14px !important;
	height: 14px !important;
}

.blockOverlay:after {
	content: "\f1ce"!important;
	font-family: "fontawesome"!important;
	border:none !important;
	font-size: 40px;
	line-height:40px;
	width: 40px !important;
	height: 40px !important;
}

Regards