These are Hong Kong's representatives. Interestingly, the boy on the left uses what seems to be a blue, chrome-plated Accele=Dracyan with a Tornado Magazine and Straight Barrel. The boy on the right instead uses a Rev=Dravise also with a Tornado Magazine and a Straight Barrel and additionally a Stabilizer.
I assume the championship only allows Core Change System products and not Emblem Charge or Pen-B. The boys are described as both
traveling to the championship despite the boy on the left holding a golden trophy. I guess they will act as a "team" there somehow.
EDIT: Taiwan's representatives:
The image is too small to determine their exact B-Daman combos.
We still don't know South Korea and Japan's representatives though.
EDIT 2: An image from the championship!
Ah, so since each country has two representatives, each will battle in 1 of 2 quarterfinals. I'm assuming this lets 2 countries win the championship or 1 country will win both, lol. It's always nice to see Master Horikawa, B-Der Ryū...and is that Blader Ken from Metal Fight Beyblade
!? There's also a female representative which is nice to see in a hobby with primarily a boy demographic.
As before, the image it too far to distinguish those B-Damans in that (I'm assuming is a) Break Bomber match...