Multiple Shareholders

I have a few questions about the verification process on Amazon. Probably somebody has the same case.
I want to make a seller account on Amazon. I’m new at Amazon so I don’t have an account on my company name. My company is an limited company with multiple shareholders. I own 70% of the shares and someone else 30%. I’m the director and I’m leading the company. The other person has only shares.
The other person (who has 30% shares) has already a company and an Amazon account. So my first question is of Amazon allowed this kind of construction were somebody has an amazon account and is shareholder by another amazon account. Note: we don’t sell the same products or are competitors in the same product category.
Amazon ask for who the beneficial owner are. So the 30% shareholder is beneficial owner in my company and off course his own company. Is this allowed? So can you be a beneficial owner on multiple amazon seller accounts? And what Amazons definition about the beneficial owner? Is that the person who have more than 25% of shares? Or is 1 share enough to be a beneficial owner?
Another question is what kind of business documents could Amazon ask for? They ask for an excerpt Chamber of Commerce, but in the excerpt Amazon could only see the board members (that’s only me) and they don’t see who the (multiple) shareholders are. So what kind of documents is Amazon gonna ask for? I guess that they need to know who they shareholders are. Do they ask for a copy of the shareholders register? Or do they only ask for who the beneficial owners are? And does they verify the beneficial owners? Does somebody has experience with that?
Thanks alot.