Get used to HK, LK, HP, HP, D+HP. Low kick will only work if you start on the ground. If you start with a jump punch starter it will only work if you start with HK not LK.
Fireball is Back, Back, HP.
ILOVEPOOP, try doing the combonation for the fireball before the JK actually connects. Even offline it still comes out after the jk so it should work.