Hello Raphael,

Yes, you can change the structure of the preloader in header.php lines 15 to 26 

https://prnt.sc/CZJI4RDmsRBw

of course, 'percentage' and 'trackbar' have animations associated with them but the preloader structure will show and hide during the loading page and when finished loading.

Regarding the mouse ball

there are some styles in the CSS that will shape the mouse ball,  but the attributes you may be interested in are the ones highlighted / bolded - 'border' and 'border-radius'

#ball {
position: fixed;
transform: translate(-50%, -50%);
width: 30px;
height: 30px;
border: 2px solid #000;
border-radius: 50%;
pointer-events: none;
opacity:1;
box-sizing:border-box;
}

.mfp-zoom-out-cur #ball {
opacity:0;
-webkit-transition: opacity 0.2s ease-in-out 0s;
transition: opacity 0.2s ease-in-out 0s;
}

.light-content #ball, #ball.over-movie,  .light-content #ball.with-icon {
border: 2px solid #fff;
border-color:#fff!important;
}

#ball:before {
font-family: FontAwesome;
content: "\f078";
font-size:6px;
width:4px;
height:8px;
line-height:8px;
text-align:center;
position:absolute;
left:10px;
top:32px;
color:#000;
opacity:0;
transform: translateY(20px);
-webkit-transform: translateY(20px);
transition: all 0.2s cubic-bezier(0.215, 0.61, 0.355, 1) 0s;
}

.light-content #ball:before {
color:#fff;
}

#ball:after {
font-family: FontAwesome;
content: "\f077";
font-size:6px;
width:4px;
height:8px;
line-height:8px;
text-align:center;
position:absolute;
left:10px;
top:-12px;
color:#000;
opacity:0;
transform: translateY(-20px);
-webkit-transform: translateY(-20px);
transition: all 0.2s cubic-bezier(0.215, 0.61, 0.355, 1) 0s;
}

.light-content #ball:before, .light-content #ball:after {
color:#fff;
}