It's possible to do a Hookshot Clip in the first room to skip through the bars, skipping the need to defeat every freezard. To do this, quickly go up to the gate and align Link's head with the third bar from the right. Wait about 5 seconds with your hookshot ready to fire and a freezard will come after you. Then aim a bit left and down and release the hookshot and you should clip through to the other side of the gate.
There are multiple ways to get through the red ice without actually needing to pour blue fire on it.
By setting up a precise angle, it is possible to superslide through the left side of the red ice. This method is difficult because the spinning blade can get in the way.
This method requires hoverboots.
This method is as simple as it looks in the video.
This can also be done as child with a Bombchu on the 8th red flash.
You can clip through the red ice on the right side of the dungeon as child by simply dropping a Bombchu on the 11th red flash.
In order to get to the back room of the Ice Cavern, you normally must collect all the silver rupees in the spinning scythe room. By performing a well angled superslide followed by a jumpslash can clip you into the gate, and the jumpslash allows you to land back in bounds on the other side.
This type of trick is useful for something like an adult max % category, or some kind of map and compass race. In order to do it, align yourself right in front of the compass chest so you are facing it. Pivot 180 degrees and drop a bomb, then pivot back. With pause buffering, it is the second frame that you take damage, the frame you would use to do a hover boost. From here you can unpause and press A to open the chest. Note that this works with the map chest as well.
You can use Ground Jumps around the room to avoid pushing the block if you have bombs. There are also some other precise jumps and moves you can do in this room: 1. You can climb on the block in its original position and jump to the platform with the rupee in the center of the room. 2. You can climb the lower platform near the gold skulltula and jump to the platform near it with the silver rupee. 3. You can do a sidehop to the right, then angle slightly back and while sliding off the edge, roll forward to get a big jump up to the ledge with the rupee in the red ice. 4. You can get the rupee in the red ice with a well angled jumpslash from the right side.
There are several ways past the last red ice before getting to the iron boots room. You can do a superslide if you have bombs, or a hover boost or a megaflip if you have bombs/chus. It is also possible with a recoil boost if you have the hover boots. When recoil boosting, equip the hover boots on the first frame you move backwards and hold forwards (counter-intuitively) to clip through the red ice.
It is possible to die just as you open the iron boots chest, meaning that you can skip the Serenade cutscene. To do this stand right in front of the iron boot chest with 1/2 of a heart or less. Shield drop a bomb and buffer until the 2nd frame of the explosion, then open the chest. If done correctly, you will open the chest and take the damage, then after the iron boots text is over you will die and skip the cutscene.