Hello,
1. Please clarify which image you would like to enlarge? Not clear enough.
2. Please add this code to the Theme Settings > Custom CSS > Global
body .swatches-select .colored-swatch, .swatches-select .image-swatch {
width: 35px;
height: 35px;
border-radius:0;
}
body .swatches-on-grid .swatch-on-grid {
width: 35px;
height: 35px;
border-radius:0;
}
The first code is for product page, the second is for product grid, change the width and height as per your needs, the border-radius has been removed.
3. see #2
4. Navigate to Woocommerce > Settings > Product > Inventory , besides you need to insert the quantity into each product.
5 Woocommerce does not provide such an option.
Best Regards