Hello,
1) To fix the Add to cart button position add the below code to Theme Options > Custom CSS
.swiper-slide .content-product .button {
display: inline-block;
}
We’ll also fix it in the next theme update.
2) Regular customer does not have admin bar at the top, so there is no error with the sticky header for the regular customer. If this is critical for you we can provide you custom code to move the sticky header below the admin bar for the admin. Do you need the custom code?
Regards