Turbo Grafx 16 won't play Japanese (PC engine) HuCards, it can ONLY play US (Turbo Grafx 16) HuCards. This is vice versa with PC Engine; PC Engine won't play US (Turbo Grafx 16) HuCards, it can ONLY play Japanese (PC Engine) HuCards.
For CDs on CD systems, it's different. On a Turbo Duo or Turbo CD, you can play both US and Japanese CD games on it, same with PC Engine Duo or PC Engine CD. So for Ys games, it won't matter. It's your choice if you want a US system or Japanese system, they will both play your Ys games. But like I said before, each system can't play the other country's HuCards.
However, if you get a US Duo or Turbo CD, you can't use Arcade Card because that is Japanese only and will only work on a Japanese system. So, you can either play HuCards in English, or play HuCards in Japanese but able to use other devices such as the Arcade Card, Arcade Card Pro, or Ten no Koe card. You can buy both, but it will cost you some money $$$.
BTW, you can buy/build converters that will allow you to play PC Engine HuCards on your US system, but the problem with them are they can cost a bit of money, and they have lots of jitter freezing problems.