Hello,

1-Yes, you can. You can remove them directly from theme files or use custom css to hide them. We recommend the use of custom css. That’s because the css is added in the Custom Css box and it’s stored in the database. So in future theme updates it will not be lost. While if you change theme files directly, these changes will be lost in case you update theme.
Please go to Tower > General Options > Custom css, add this code:

.portfolio_single h4 {
    display: none;
}

2-Yes, it will go up just the height of the title you are removing. See screenshot: https://postimg.cc/image/71lr7u0vh/

3-Sorry but this is not possible.
4-The loader is an image. You can change it, using a image processing program.
The image is located in \tower\css\oval.svg

Best regards!