Alright, I main both of these characters and I've played this matchup a ton.
Zelda suffers a ton from characters who outrange her because she has little to no safe approach options. Shulk has the best range in the game, so this is a huge problem for her. Her best option will be to bait Shulk into an option since he has a lot of lag on most moves, and punish with a grab, dtilt, or whatever, but Shulk just needs to play carefully and avoid that. Shulk's main goal in this MU is to outspace Zelda since she doesn't have many options from far away and can be rather dangerous up close. I'd recommend Speed and Buster for this.
Since I just talked about Art usage, I'l go into further detail. Jump will have the same uses as usual, but be careful with it on due to the extra damage taken: Zelda has some really damaging low percent strings such as dtilt --> jab --> dthrow --> nair. Speed is very useful in neutral, as per usual. Buster is very good IF you can keep Zelda out with nair, dtilt, and MALLC bair/fair.
I didn't talk about Shield or Smash in that paragraph because I need to talk about something else...the elevator. If any of you Shulk mains don't know, the elevator is just a nickname for Farore's Wind disappear to reappear. This move is SOOOOO DANGEROUS. In any Art, you're going to want to be extremely careful with how you hit Zelda's shield. If you leave yourself open, oh look, a frame 7 OOS move that kills you at 76% with no rage. With about 150% rage, it'll kill you at about 45%
in Vanilla. This is why I think Smash is a horrible art in this matchup
. With no DI or rage on Wii U FD, the elevator kills Smash Shulk at 45%. With max rage (150%), the KO sparks start flashing at
14%. Since Smash also does less shield pushback due to lower damage output, you're also more susceptible to the elevator OOS.
Regarding Shield, it's very good in this MU since it'll make the 2nd hit of Farore's (the one with a ton of knockback) not connect until verrrryy high percents.
When recovering, be super careful. Zelda has arguably one of the best spikes in the game and she can go super deep. If customs are on, watch out for the Phantom because the best and most commonly used one does a ton of damage and semispikes you at a horrible angle. If Zelda also just lets the Phantom sit at the ledge while you use Air Slash, you can end up sliding right past the ledge and getting gimped because the Phantom slows your momentum if you try to go through it.
Platforms are lolsobad for Zelda, so take her somewhere with them, BUT NOT TOWN AND CITY OR HALBERD. In this MU, low ceilings are your enemy and Zelda's bff :^)
Imo,
:
60:40
I know I said a ton of scary stuff that she can do, but just remember that she's still Zelda lol. Exploit her weaknesses and she can have a lot of trouble