discount set up

[LTDMoments]

Can I create a discount for abandoned cart and customer favorites without them being duplicated? 

[JJewellerySuppliesUK]

Do you mean people getting a discount for both?  If so, then only one discount is offered at any time. 

You need to use Etsy's tool to set them up:  How to Set Up Sales and Discounts for Your Shop – Etsy

[NoFrogsAllowed]

Sales and coupons do not stack unless you have a sale or coupon for free shipping.  If an item is eligible for 2 or more sales, Etsy gives the buyer the one that is the best deal unless the buyer enters a coupon code in which case sale price reverts to the original price and the buyer gets the coupon discount.