Basically, You need the resell permit so that you do not have to pay tax when buying wholesale. you would collect the tax from the person who buys from you and pay those taxes when the time comes.
you need the business license to prove that you run a legitimate business (in a non-residential area)as they don't want people selling out of homes, garages or ebay. and undercutting LFS', which would put them out of business.
most will also ask for 3 trade references from wholesalers you do business with. i.e. invoices from past orders with other wholesalers.
most will also want a voided copy of your business check faxed to them as well as your business email, phone, and fax numbers.
and your business checking acount on file, or a major credit card on file.
usually minimum orders are around ($300 - $350.00), not including shipping. add shipping on top of that. anywhere from 50 - 75.00 per box. (could be more or less depending how far your live from distributor.) Usually, they ship via the airlines, meaning you would have to go to the airport to pickup shipments. If you live close, you may be able to pick-up the coral yourself or have it shipped with courier.
I would not put any coral from a wholesaler in a display tank directly without being quarantined first, you would need a separate frag tank just to quarantine your new shipment of corals and then another tank to move the frags to.
anyways, this is my experience. there may be some out there that require more, or less. All the wholesalers I have experience with are here on the west coast, I'm not sure If they operate any differently over there.