1. Did you mean is to make the testimonial slider autoplay?
2. I’m not quite sure what you mean, can you provide me the page url that you referring to for better understanding. So i can easily to help you.
3. It will need to add some custom css code to achieve that.
4. It seems you question have been answered right here http://support.jegtheme.com/forums/topic/possible-to-change-slider-size/
5. You can add alt images in the Media Library. But the alt text will not show up on Full page gallery and you need to make some custom change on those page layout.