Introduction:
While instant/while running 2 launches on CH and gives an escapable knockdown on hit, chances are you're not going to land it in either case and instead must deal with what options are available to you on block. Simply put i/WR 2 is +4 on block and that advantage is only valid when the opponent is left close to you, on certain side steps and possibly at max range, they'll be pushed too far away to make the below options possible.
Valid Options (in decreasing frame window size):
i10 - 1,2 CH confirm: 2nd hit is mid catching twitch duck
i11 - f+1+4_2+3 instant throw: will catch everything, but vulnerable to ducking and can be escaped
i12 - 4,1: is a great attack if you think they're going to attack, but otherwise weak
i12 - 4,3: is fairly risky but will catch standing attacks and SS/SW if they're slow on the draw
i12 - d/f+4: will catch all options except SS/SW
i13 - d/f+1,4: CH confirm will catch all options except SS/SW
Other Options:
i14 - b+3: will catch SS/SW and slower attacks, but vulnerable to twitch ducking and trades on jabs
i15 - b+4,3: will catch slower attacks and is a hard counter to punch parries
i15 - b+4,2,1 CH confirm: will catch slower attacks and sets up +8 on CH
i15 - d/f+2: will catch twitch ducking and slower attacks for full launch, vulnerable to jabs and panic SMid attacks
i16 - u/f+3: will low crush and wallsplat/knd, but unfortunately can be jabbed out of the air for float
i22 - u/f+4: will low crush most lows and can follow up for small combo, but it too can be jabbed mid-air