marcelo_95 I just have couple of questions.
1.-How do you handle renturns if you don't have a location to recive them or they can send the Oberlo suppliers?
2.-Is there any difference or rules I should take in consideration when droppshipping to EU?
3.-When using affiliates/embasadors in USA does that mean you have nexus there and you must pay sales taxes, or it has to be big volume of sale to qualify for that?
4.-How do you handle sales taxes or vat?
5. Is there any apps or things we should put in or sites to convert more sales?
6.- is there any other way to make scarcity, because the hurrify thing seems scammy and tacky?
7.-Any advice on building an instagram with followers that specific to the niche?
Hey Marcelo - awesome questions!
1.) Whenever someone wants to return a product, I send them a refund and tell my customers they can keep the product. It's a super easy way to deal with refunds.
2.) - 4.) Please understand that I'm not allowed to give legal advice. As this is a very sensible and important topic, I can highly recommend consulting a lawyer and/or accountant.
5.) The best advice I can give you about this is to treat your customers well; before and after the sale. Trust converts 
No app can do that for you.
6.) Working with scarcity apps and tools do not work for all kind of products and niches. I would actually suggest trying if a product page without a sale-app converts better. If YOU feel its scammy, chances are high your customers feel so, too.
7.) Instagram is awesome, the opportunities seem to be endless! However, I wouldn't focus on follower numbers. Instagram is a content game and people are on there to discover awesome images! If you focus on the content, people will automatically follow you because they want to see more.
Although I couldn't answer all of your questions I hope it still helps
