From what I heard, PairPuri ended at vol. 10 (Fuji and Shishido). And I have a gut feeling that those twenty people paired up in those volumes will be the future top 20 U-17 Japan representatives. Except for Tezuka, since he's gone to Germany already. I mean, Konomi Takeshi's already given us foreshadow for the possible upcoming match arrangements...(Sanada and Kaidou training together and getting mad at Tanegashima for taking away their water bottles; Akutsu being angered by Oomagari ordering him to put Sengoku's book back; Kite and Marui practicing together, maybe with Kimijima?
Oh, and of course Ryoma, who just might go against Byoud...