Just buy a stealth eBay account in the USA and sell on that account on the eBay.com marketplace.
Order the amazon goods from any account you may have, as there is no restrictions to using amazon.com regardless of where you are located.
Just a heads up, don't try to sell outside of the country the eBay account is registered to when you first start out. This is a very common reason for suspension. i.e. if you register on eBay UK, don't attempt to list items on eBay sites that are outside the UK.
Your query is also very broad, i'd focus on one platform before venturing out. Start with eBay, Amazon can get tricky.
Ambitious but I dont think eBay would have the money to buy Amazon
If you want to sell on eBay.com and you are not in the US you will end up having a few issues. Best to sell in your own country first to build up some trust then move over to .com
Just a heads up, don't try to sell outside of the country the eBay account is registered to when you first start out. This is a very common reason for suspension. i.e. if you register on eBay UK, don't attempt to list items on eBay sites that are outside the UK.
Your query is also very broad, i'd focus on one platform before venturing out. Start with eBay, Amazon can get tricky.