Long Term Business Visa Nz

I have informally helped a Thai couple I know with completing an application for the above NZ1058. They are almost ready to submit it. The cost is very high $2800NZ presumably that is to deter applications from people who aren't serious. Would that be right?

Secondly, they wish to open a shop there and eventually settle if it all works out, I think their application looks pretty good, however at one point details of their existing businesses in Thailand are required, financial statements, tax returns, licenses, organisation charts or a report on these things from an internationally recognised accounting firm are quoted as the sorts of things Kiwi immigration is looking for. Despite their businesses employing 25 or more people and making substantial profits they have none of these, all they are able to show would be bank deposits. Would that be sufficient?

Lastly what would a migration agent charge to oversee this process for them?