when the opponent is close after AA, grab (really good damage for lucario, so look for this opportunity)
when far, AAA or AA -> dtilt
when predicting a dodge, you can even try AA fsmash/ftilt since they omnom through lots of dodge animations
also AA -> FP is occasionally useful, but DO NOT make it a staple, you will get punished hard if you do against good opponents, nonetheless, a useful mixup to throw in occasionally, as FP often gets you a lot of string power.
jab in general is pretty good, as it has tilt-esque range for a semi-jab level speed (frame 6 is generally faster than most anti-air ftilts), and gets you a good amount of reward for relatively little risk, plus has true advantage (not enough to make grab a legitimate combo, but more than ones like Falco).