Amazon VAT Compliance Made Simple –

It depends on the fact where your business is registered for tax purposes, whether you are conducting sales as a sole trader or another type of business. In most cases, Amazon will require your VAT ID from your country of residence. 
There are numerous situations where Amazon will require you to register in more than one EU member state. One of the cases is if you store your inventory in more than one location, such as Amazon FBA facilities based in different countries. 

Yes, you can have more than one Amazon seller account, but only if you comply with specific requirements. Amazon allows vendors to have multiple accounts if they, e.g., offer different products, and in that way transparently can demonstrate the “need” or benefits of having more than one seller account. 
Can I supply digital products via the Amazon marketplace? 
Yes, there is an option to offer digital products via the Amazon marketplace, but with many restrictions and limitations.

To guarantee the highest level of professionalism and quality to its customers, Amazon has developed a customized policy and certification system for third-party service providers. There are third-party service providers that are willing to put in additional effort to become Amazon SPN certified. 
To become Amazon SPN certified, the service provider needs to comply with specific requirements mandated by the marketplace. Only after being reviewed by the Amazon team will the service provider become certified. The primary difference between Amazon service providers that are accredited and the ones that aren’t is that they are, by default, more aware of how the marketplace works. 
Service provider network Amazon is an exclusive network of vetted service providers.

There aren’t, per se, default restrictions mandated by Amazon on this. The Amazon vendors have the freedom to delegate their responsibilities to service providers, which they find proper for a limited number of tasks.

The Amazon worldwide SPN network represents a marketplace-approved database of third-party service providers that have been vetted and certified by Amazon representatives. The service providers that can be traced back to Amazon’s directory are those that have successfully passed Amazon’s verification process. 
Within the Amazon SPN network, interested third-party marketplace vendors can find a vast array of different service providers whose primary responsibility is to assist e-commerce merchants with their operations through Amazon channels. 
Only registered Amazon sellers can access and, at a later stage, reach out to one or more of the vetted service providers listed within SPN Amazon. The database currently comprises approximately 800 certified service providers from various sectors. 
All listed Amazon service providers have passed official screening by Amazon and are continuously updating their offerings to align with the standards set by the marketplace. Registered merchants have the option to access the database, consult reviews left by other merchants, and acquire services from one or more vetted service providers. 
Collaborating with service providers that are part of the Amazon SPN services network offers numerous advantages to third-party suppliers seeking a specific type of service to enhance their business operations on the marketplace. 
Leveraging Amazon SPN means using vetted and specialized service providers that have gained the ins and outs of the Amazon core business principles.