There are some complicated laws surrounding business formation by a non-EU national
Well, actually, the only difference between non-EU national and EU national (in tems of biz setup), we can't register as a sole proprietor, so we need to stick with Sp zoo or SA.
As for accountant advice vs forum advice. You know, before speaking to accountant it is good to gather info from various sources, so you'll be able to distinguish bad accountant from a good one. As you can see, there are various points of view on VAT question, so I guess, every accountant has his own point of view...and where is the truth? Only observation can tell or... tax office inspection, which isn't great at all.
Strange, in the last 15 years or so I never bought anything over the Internet without an invoice.
Hmmm....very often, you don't receive it, only order summary. If this will work as an invoice then great. Moreover, this is true, often you don't get an invoice, especially, when you pay via paypal.