So, am I correct on his gameplay mechanics?
For every attack that involve his bat, Junpei gains a single, whether it is a normal or special. So a combo that involves him hitting his opponent with the bat 3 times, makes the bases full. A home run super will grant him 4 bases! He can also hit his opponents projectiles for bases as well! (Yukiko 5B, Sho's knife throw, etc.). Unsure if this works for like stuff like Ziodyne, probably not.
He gains a ball for every blocked attack that involves his bat (4 balls = single).
A whiffed bat normal/special gives him a strike (3 strikes = 1 out)
He gets an out for each instance he gets hit, after going back to neutral. Getting hit by a Burst do count as an out.
3 outs will clear the bases.
Gaining 10 runs will power up Junpei automatically. He will remain in this state for the remainder of the match.
Attacks seem to count for bases even after the round ends. So corpse beating is actually encouraged with Junpei. Lol!
Getting a base hit will reset the strikes and balls count.