Yeah pretty sure the only way to convert to business account is to do it manually on a phone and link to a facebook page everytime.
Yeah I use the embedded browser for everything
I still use those sites above for my smaller accounts when phone verifying
Explain your reasoning about the non-pva i dont understand the question completely
Animal and Travel are the easiest to grow and sell.
Its easier to sell smaller accounts so far in my experience, not to many people want to spend more than $250 on an account unless they are experienced and have had past success with social media. But that could also be a trust factor with so many people scamming now-a-days.
I think after an account hits 10-20K it becomes very hard to price it so I usually sell under that.