At present there is no option to control the looping. I have modified the code to help specify that the looping be disabled through a parameter called loop passed to the [iphone_slider loop=false] shortcode. Have attached the file with the change made. Will be part of next update and hence you should not lose these changes if you update. Replace the file
Regarding that strange icon, I see that on my iPhone too but never on the desktop. Can you try replacing the icon with 2 or 1 and see if the problem recurs? Also, looks you are mixing up icomoon font icons’ CSS with your own for these custom icons created by you. If you are going to have your own icon, better to go for a separate CSS which controls these icons instead of overriding the icomoon CSS since you are not going to use their icons anyway. Thanks.