Can you please share your site URL with us. We will check the issues on your site and help to solve it. (for 1 & 2)
4. If you want to change the number of the slider, you need more than 5 slider items and check the options on slider setting(This features is available only on premium version).
5. Slider setting have various options on the premium version, kindly check all settings there.
Please check all the setting there on the customizer.