For the first issue, you can use the value slideshow_speed=3000 or any other value of your choice. It sets the amount of time between each slideshow interval, in milliseconds.
Other attributes are animation_speed (takes numbers – default is 600), animation (fade or slide).
Second issue – that’s how the flexslider carousel operates. At times, the images get cut off a little bit at the right. I think it’s a little more intuitive with touchscreen devices where the user can just slide using touch exactly the amount required. I am looking for a better solution myself. Hope it’s not too much of an issue. As an alternative you can use the shortcodes documented in the page –
https://www.livemeshthemes.com/enigmatic/blog-shortcodes-2/
Hope this helps.