A question about carrying over arena progress in NG+

[Desticler]

What exactly gets carried over when you choose to carry over arena progress? Originally, I assumed that it would carry over what medals you have, all arena coins on hand, and all purchased arena items, along with not being able to buy extra copies. In other words, purchase history would be saved.
Then I read in a gamefaqs guide that you can buy extra copies of armor in the arena shop in NG+, which, if true, would mean purchase history is not saved. Which would mean that if your progress on gaining coins also carried over, you could get locked out of buying everything if you buy extra copies, which leads me to believe that the progress on gaining coins isn't carried over. But like, the medals would 100% have to carry over, if they didn't there'd basically be nothing to carry over with the arena anymore, so does the game display your best medals and scores from the past playthrough, while you gain coins as if you didn't gain any medals yet? And looking back at the gamefaqs guide, the author of that guide said they recommend to carry over everything, which to me felt like an implication to carry over arena progress too. What if this was just poor phrasing on their end? What if they meant that if you don't carry over arena progress, you keep the armor still? If so, then what other items get carried over from arena shop if you don't carry over arena progress? Do the 5 "extra CP" items carry over as well, with or without carrying over arena progress?
If I wanted to check all this myself, I'd need to play NG+ all the way through to chapter 10 where the arena gets unlocked. That is a long time, so I'd rather know exactly what gets carried over before I start NG+. This would let me know whether I should make some arena progress now to make purchasing everything easier in NG+, or if it never gets easier so I could do it either now or later.

[LuVenBen]

you earn back your coins when you chose to keep arena progress. ie. if you had 10 gold medals in your OG save, your NG+ will also have 10000 coins regardless of how many you spent