don't bother using orbies. unless link is daft enough to stand still and charge an arrow with the
intention of hitting the orbies, it's not going to yield good reward. moreover, link can bait you into putting up the orbies and then hit with the arrow during cooldown, since he can hold his arrow indefinitely. that and, as
ReRaze
said, link doesn't have much cooldown on his specials, so the chances of using it are practically non-existent in high-level play.
a good link will not let you reflect their projectiles. don't bother. powershielding is an infinitely safer and more practical option.
do not hold shield indefinitely. that's just begging to be punished with link's tether grab. powershield between projectiles and try to approach or force link to approach, depending on the current situation. neutral in this matchup is about stage control and responding to constant pressure from projectiles. link needs to set up with projectiles and zone you into an unsafe position in neutral, since his high-commitment moves can't be thrown out relentlessly. patience is vital in this matchup. just don't be frustrated and get impatient due to pressure and know how to navigate the wall of projectiles you will no doubt have to fight through.
edit: very brief rundown of how i'd suggest pit react to projectiles (note that powershielding or spotdodging are options for most projectiles, but not necessarily the best option; if possible, the best option is often to just not be in range of the projectile, so you need to know how link can zone and control the stage if you decide to avoid it outright):
- arrows: powershield, spotdodge or outcamp with arrow-jumping. powershielding negates arrows and can be used to approach link. the purely horizontal trajectory means you can't get camped out in the air and multiple jumps mean pit can camp out link more effectively (if he wants to commit to arrow-camping, which is kinda silly but whatevs~) and force him to use a different option. it can be used to zone you on the ground if you don't powershield, so if he forces you to jump, be wary of boomerang and z-air punish. camping tool with good range, but predictable trajectory. very rarely charged fully or held, more useful for mid-range pressure and zoning.
- boomerang: powershield, spotdodge or jump. powershielding is, again, a good way to beat boomerang's zoning potential and approach link. the ability to aim boomerang's trajectory means arrow-jumping isn't really an option. jumping over it is a safe option if you're out of link's range, just be wary of zoning, airdodge baiting and z-air. i would advise against riding the wind unless you're sure about hat you're doing and ho to approach with it, since it's a very easy setup for link if you get pulled right back into his space. useful for damage, setups and zoning by limiting your movement options, but it doesn't have the rapid camping potential of arrows.
- bomb: shield (debatably better than powershielding), spotdodge or grab. powershielding the bomb itself is not as effective here if it's just the bomb being thrown at you, since the bomb will remain active if you powershield (in other words, it will just bounce off shield and continue to explode); on the other hand, default shielding it will render it inactive, so bear that in mind when you respond to it. try grab it if you can, practice air-grabbing or catching it with another move (dash attack is a good choice if you're within range to punish link); just remember to release it before it explodes, and bear in mind that link may set up a bomb-grab to prevent you from immediately using your next move (since the input for normal move or grab will throw the bomb instead). this is more of a trap than a true projectile, as the timed hitbox means it can still be a threat even if you shield it. keep an eye on how bombs are used, as it is a strong embellishment to link's projectile game.
edit: did some research on bomb properties. it's a bit complex, so check
this thread for further information.
- z-air: powershield or spotdodge. not a true projectile, but worth mentioning. z-air is a low-commitment, high-range option that can be used to space and followup from projectile zoning. approaching link can be difficult due to z-air, and it helps him approach safely himself, and it can be used at the ledge to keep you from punishing his getup. a good spacing tool that you need to keep track of.
- grab: spotdodge or roll behind. again, not a true projectile, but worth mentioning. link's tether grab has good range, is reasonably fast and sets up for a fast pummel, u-throw -> u-air combos and u-throw itself can kill at just higher than 100%. if you're being zoned with projectiles and link has good stage control, he can throw out grab as a surprise option and get great reward off of it. be aware of its range and try to avoid situations here link can get the grab (e.g. if you shield too often or whiff an unsafe move). mix up your powershields with spotdodges to keep him guessing and make it difficult to punish with grab. if you can roll behind him hen he uses it, you have an opening to punish. not something he will use very often, but worth bearing in mind.