1. By default the user can select the store from the dropdown or create one. If a person is making a legitimate coupon post it's unlikely they would select a different store on purpose, but if you were looking to make such restrictions it would require customization on your part.
2. You can set a coupon price, but featured coupons are added from within the Clipper admin for the slider, so there are no paid featured coupon options. The slider works best with 5+ coupons listed.
3. There is no specific option for this in the Clipper admin dashboard, so again this would require customization.
Our themes are not encrypted, so you are free to make modifications if you wish. Thanks.