The intended path to Ikana involves freezing the octoroks with ice arrows to make platforms across the river. However, from a somewhat precise position, it is possible to hookshot to the first tree from across the water. Stand roughly where shown in the video (between two dark textures on the ground) and slash to the edge. Hookshot towards the bottom of the tree to be able to reach. The octoroks will each shoot one rock as Link approaches, but as long as they are off screen, they will not continue shooting.
There are many ways to do this. The video below shows the three methods described here.
To skip the intro cutscene, enter with a bottle in hand, pause within a 2f window, pause buffer L + R, and then pause buffer L + R + bottle on the next frame. Step on the switch, then step off and wait until the door makes a sound. Then step back on. The camera will be awkward once you take control of Kafei; hold approximately up-right to get him to the block to complete the first puzzle so you can regain control of Link.
After doing the intro cutscene skip, failing the room skips (see below) by killing enemies as Link or by getting attacked through a door will give you control of Kafei but keep the camera on Link, which looks like a softlock. However, it is possible to complete Kafei's puzzles blind, as shown here.
There are multiple ways to skip the puzzles in Sakon's Hideout and go directly to the end. Be careful when attempting these, as falling onto the wrong side or accidentally killing an enemy can result in having control of one character while the other is on screen, which is very awkward.
The babas must be just a little bit away from the wall for Link to squeeze in between and hookshot clip. Jumpslash after the first hookshot clip in order to land on the ground. After the second hookshot clip, the sidehops must follow the camera reorientations: 2 right, 4 left.
This video demonstrates collecting purple rupees from two of the first three poes.
After exiting the poe hut, sidehop right. Shoot Tingle's balloon, then read the poe hut sign before the cutscene begins. If done correctly, the balloon explosion will be visible in the background. Wait for a moment before clearing the sign text; otherwise, the cutscene will play afterward anyway.
Get ISG, then megaflip into a chu hover. Hover twice more and then backflip to the platform.
There are multiple methods of getting up to the Captain's Hat chest early and multiple methods of opening it with the fire still surrounding it, skipping the chase, fight, and cutscene with Captain Keeta.
This method is slightly slower than the weirdshot method but has no frame perfect components. However, it is risky, as Link will void if touched by flame as Zora, or if you transform Zora while Link is still on fire after touching the flame.
After you play Sonata of Awakening, Keeta is supposed to have enough time to get past the first fire barrier. However, running into Keeta's sleeping collision and shield dropping a bomb right before playing Sonata causes Keeta to get stunned by the bomb during the awakening cutscene, making it possible to get in front of it and start the fight without fighting any stalchildren to take down the fire barriers.
This method is easy to do quickly but is only possible on JP because power crouch stabbing is patched on Eng. Shoot Keeta with an arrow to stun it, then store a deku stick jumpslash. Power crouch stab Keeta six times to win the fight. Try to trap Keeta against the wall to keep it within stabbing range on the first four hits. On the last two hits, Keeta will jump, so roll towards the camera when dodging the jump so that Keeta stays on screen when it lands.
Keeta is weak to goron pounds, so this method is useful when playing on Eng where power crouch stabbing isn't possible. After the cutscene, roll in front of Keeta to start the fight, then hit it with six pounds. This is difficult to do consistently because Keeta can push Link away while he's in the air, but it is helpful to continue holding A after the pound lands on the ground so that the hitbox stays active as long as possible. When Keeta jumps on the final two hits, roll towards the camera when dodging the jumps so that Keeta stays on screen when it lands.
After defeating Keeta, the jump to the Captain's Hat chest is somewhat tricky. The video below shows four methods of reaching the other side:
If you fail the jump to the Captain's Hat chest, there are two good backups that don't involve rolling all the way around the track.
Voiding out as the cutscene begins skips the cutscene. The video below goes over a way to time this consistently.
Target the back of the headstone, shield turn up-left, move to the position shown, and tap sidehop into the grave.
Use a bomb to long jump to the Day 2 grave entrance platform as shown in this video. A jumpslash can be added to avoid grabbing the ledge at the end.
There are multiple ways to enter Dampe's grave without using the Captain's Hat.
Get ISG off a bomb (faster) or the headstone text (slower). Hover once up the headstone, then put on a transformation mask to enter the grave.
To lead Dampe around, target him as human without any masks on and walk slowly towards your destination. There are three blue flames to dig up to spawn the big poe, and only four of the dig spots in the room can contain a blue flame. From the headstone entrance, these are the near right patch, the center patch, the raised patch on the left, and the raised patch in the back right. This is also the order that these patches are checked in. "Good Dampe" refers to the three blue flames being under the first three patches checked (25% chance); "Bad Dampe" refers to finding an empty patch and needing to check all four (75% chance), which costs about a minute. When approaching the two rising platforms, a wallmaster will try to snatch Link.
If using bomb timestop as shown in the video, only begin moving just before the bomb explodes; otherwise, Link will move off the switch too early and cause the cutscene to play before you can get timestop.
This trick exploits the fact that arrows pause and don't interact with the Stone Tower blocks during the cutscenes while they're moving. These setups coordinate a light arrow shot and stepping on a switch so that the light arrow hasn't yet hit the block before the cutscene starts but is fully behind the block when the cutscene ends.
Goron roll forward off the platform. Very soon after leaving the platform, release A and hold down and target to drift backwards and land on the entrance platform. Be targeted while landing to avoid damage animation.