For shipping them , U haul sells boxes in varying sizes that will work......a small wardrobe carton or maybe a dish barrel would be the ticket.
Most places that coat them ( I have been doing a bit of homework on this in the last few days ) ship them back in the carton they were sent to them in , so a couple bucks worth of bubble wrap or similar isn't a bad idea either.
As far as reputable outfits , some of the big names aren't quite honest with some of their claims regarding coating inside and out.
And like anything else , you get what you pay for.
The last set of ceramic coated headers I saw that looked anything like the O.P.'s were run with a load of bad gas and it BBQ'ed the coating right off of them.
But it is surprising that they look that bad after so short of a time, and it's good to hear that they are stepping up for you.