Regarding setting up accounts, you only need to set up one eBay account. From that account, you can then log into any international eBay and post your listing. So for example, if you are registered on eBay UK and want to list on eBay US, then you just log into eBay US with your account information and post your listing there.
Just bare in mind that different eBays have different pricing structures for different genres, so you want to make sure you are aware of all that before posting.
Regarding shipping, if you are dropshipping products, then that can come down to your suppliers shipping policy. If you are selling direct, then you have to develop your own shipping strategy/policy.
Payments methods, PayPal is available through every eBay, but different countries may offer different options outside of PayPal as well.