I think Sheik does much better in this match than Zelda does. Sheik actually has the speed to get around and punish TL's projectiles, as well as beat him in the air. Because of her speed, she's also allowed to keep more distance from TL while still being able to approach and punish.
Zelda is like a whale in this match-up. Because she's so slow and there's so much going on, she needs to keep control of the center of the stage. Counterspamming TL doesn't make for a fun battle at all, and Naryu's can definitely be baited and punished if you intend to use it.
Power shielding is definitely the better option to use against TL's projectiles. If you keep him at mid range, you can punish the lag of his b moves after perfect shielding them. His bombs will bounce off your shield, and after that they won't harm anyone until they hit the ground. You can catch them with the z-button and c-stick thow them back at him. The only time I would use Naryu's against his projectiles is when the boomerang is coming back from behind you -- it will go straight through you and hit TL.
A lot like Marth, he can space you out with nairs and bairs, but he can't approach you with them unless he wants to eat an up smash or lightning kick out of shield. He also has very laggy smashes which can be punished at close range. Dsmash hands down beats anything he can do to you close range, and dtilt is as fast as his jab. Dsmashes are your friend in this match as they put TL in a position to be edge guarded/spiked.
If TL didn't have his projectiles, the match would be in Zelda's favor. He has no really safe approaches. His zair is kind of annoying, but his follow-ups can be avoided and occasionally punished (zair to grab) if they whiff. At close range, Zelda wins on the ground against him both grounded and aerial. His projectiles make things more difficult because they allow him to rack up damage, keep his kill moves fresh, and run away to a safe place all at the same time.
It's necessary for Zelda to control the spacing in the matchup. Toon Link can run away from her, but he will have a very difficult time crossing her up without being punished. At mid-range where you'll want to keep him, Zelda does have options against his projectiles. Powershield to dash attacks/grabs work well enough. She can also mix in dtilt locks which can do very good damage to TL and set him up for a dsmash to spike. TL also has a pretty wide frame for a little guy making him a not-too-difficult lightning kick target. He can be hit with a rising bair.
I'm inclined to think this is 55-45 in Zelda's favor because TL can make things very difficult with his projectiles. Zelda has the option to trade hits in a projectile match, but also a few methods of punishing his projectiles at mid range. She also has more and faster killing options than TL and an edge guard advantage.