Sorry to burst your bubble on this, but any of the Lightning kick related combos are not fully guaranteed. (Especially on anyone other than Bowser.) If the opponent jumps or air dodges quick enough, then the kick is lost.
Though, it has been shown that Zelda still has a good chance at getting damage off of Dthrow by mixing up three different options based on the opponent's reaction.
first, depending on if they DI in or at all, NAir is very fast and reliable at catching them.
Second is UAir. It can catch jumpers and has better vertical range.
Third is a tough Airdodge read. This is where you simply jump without attacking, and if they Airdodge, you can hit them during end lag with a well-timed kick. I should also note that if they DI it behind Zelda (AKA, away.) you can make the lightning kick read easier.
You'll have to be careful though, as these three option don't cover every type of reaction. Once an opponent takes too much percent, all of these can be escaped if the opponent is willing to use their second jump. Do note though that this can put them in a riskier situation when tying to land.
I hope this helps! ^ ^