As Ganondorf? Tipman at the edge, tipman offstage out of his up+B (I'd try floating right by the ledge and DJ uair) are things I'd suggest messing around with. If you can do DJ dair from the ledge to onstage (that is, on ledge, drop -> DJ -> dair and the dair comes out), grabbing ledge and doing that isn't an edgeguard but should KO him around 100% on most stages if I'm not mistaken - and the same principle works with fair on small stages. Be wary that he can aura cancel to avoid endlag of his recovery, but forcing him to burn aura is usually not a bad thing to do since it hurts his neutral and KO options.
Alternatively fullhop offstage, bait down+B, and DJ uair or bair as appropriate. Down+b is silly (in a good way, I think it's important to Lucario) but it DOES have endlag, so hitting him out of the end of that will really ruin his day. Fun fact - Lucario can go under Dreamland with an aura charge by using down+b -> dair cancel (slows fallspeed, maintains horizontal momentum) -> DJ -> up+B (requires decent steering), so it's no wonder gimping him is a struggle. But hit him out over and over and his recovery gets worse as he loses elements of it (down+B, jump, aura charges), so just intercepting him is good when you can.
Also I'm pretty sure Lucario bops Ganondorf hard because he actually should win in neutral (as far as I know) and Lucario basically has the best punish game of any character (outside of maybe counting Jigg's rest). Do you play other characters besides Ganondorf? This may be a good person to use a secondary against...