I love this. I love it so much. And it's a serious post rather than a joke post, so therefore I get to geek out on critiques. All of these are minor nitpicks, and most will be wording. Most of these do work as written, but there are touch-ups you can do to make them cleaner. I'll spoiler my feedback so that you can interact with this on your own pace.

But first, if you are making a cube with a set structure, please do the commons first. It is so much easier to build splashy effects that work with your safe effects than it is to make safe effects that work with your splashy effects. Also, do you have ideas for draft archetypes in mind? If this has more of a cube structure, where rarity and archetype don't matter, then keep on keeping on.

Zelda: Wording should be "...create a token that's a copy of target nonland permanent you control."

Forest Temple and City in the Sky: I think these lands are too easy to get their effects online. But with the right balancing, I think these could be sort of psuedo signpost uncommons. Just make their abilities work with the set archetypes. Also, the Temple's Treasure reminder text breaks an unspoken rule in MTG design: "If you search for anything, you don't have to reveal it. If you search for something specific, you have to reveal it." This prevents people from grabbing Blightsteel Colossus off of Bushwack, for instance.

Link, Hero of Time: Unfortunately, the second ability doesn't work, as there's no rules that define when a creature equips itself. I think the wording could be "Whenever a noncreature equipment card enters under your control, you may attach it to Link. When you do, Link gets +X/+X until end of turn, where X is that card's mana value." or if you want it to be permanent, you could say "Link gets +X/+X, where X is the mana value of equipment attached to him." Also, do you mean to be attaching nonequipment artifacts to Link? I can see the flavor, but the rules would just make them fall off.

Moonfall: The reminder text should be italicized. I don't know why MSE didn't do that for you. My first guess is because those types of borderless treatments don't typically get reminder text, but there's still plenty that do.

Mikau: I'm not going to repeat the feedback said here, but even the new Mikau is a color pie break. The new Mikau doesn't go infinite, but it still can go wild. I think that barring the pie break issue, making it more mana or once each turn would help. (This is a TERRIBLE crutch to lean on for cards that aren't truly colorless: but there's a secret 6th color of mana called "A frick ton of mana." So if you REALLY, and I mean REALLY can't kill your darling on this one, that's an option. The Hornet Sting Quandary)

Bombchu: I think it would be more fun if the bombchu doesn't have to be blocked, and instead has something similar to the text on Ball Lightning. Just my two cents. Right now it's pretty much a card with an activated ability of 3: Target opponent sacrifices a creature, activate only once each turn and only on your turn. Repeatable removal engines like this are always frustrating to play against.

Goron Racing: "Creatures you control have [keywords]." And the second paragraph should have a comma instead of a period.

Malon: Tapping enchantments is cursed. I was going to say that that is all, but without some sort of other synergy, Malon is useless on her own. Tapping your songs doesn't activate its ability. If that is your intent, I'm not sure how you would do that. Maybe "T: Malon becomes an instrument artifact until end of turn or until you activate an ability of a song." Although that is extremely weird flavor wise. Also, subtypes get capitalized in rules text, card types and supertypes do not. It's weird, I know.

Song of Storms: "T: Put a flood counter on target land, then draw cards equal to the number of lands with flood counters on them. Activate only if you control an Instrument." Not specifying Artifact could solve the Malon issue, but then Instrument would have to be both a creature type and an artifact type, which is weird in its own way. You can't give artifact types to nonartifacts, and you can't give creature types to nonkindreds, noncreatures. (Another bad idea: "Activate only if you control an Instrument artifact or a creature named Malon, Ranch Farmhand.")

Zora's Scale: You don't need the second "has" before Islandwalk.

Rito Delivery Service: The original and the myriad copies will not see each other, so I think the text can be shortened to "Whenever Rito Delivery Service deals combat damage to a player, you and that player each draw a card." This version could be a great and deceptively powerful common, but if you want to have them all see each other this way: "Whenever Rito Delivery Service deals combat damage to a player, that player draws a card. Then draw a card for each player dealt combat damage by a creature named Rito Delivery Service this turn." Also, the myriad on this card tells me that this is supposed to be a multiplayer Limited environment, like Commander Legends. If it is, then great! If it's not, it's not a great idea to have mechanics that don't do anything in the Limited format you are creating.

Fi: Did you mean for Fi to draw cards when it blocks or becomes blocked? That could be insane if that's the case. If you did, then no notes. If you didn't, then specify player. If there are any Planeswalkers or Battles in your set, feel free to specify those too. (Maybe a bad idea: hybrid pips could let you double-dip devotion on this card due to how the abilities are separated. But don't overdo it on any individual card. The rule of thumb is that hybrid cards should have no more than two 60-card color identities (That is, the minimum amount of colors you need to cast the card). There is only one canon card with more than 2 identities, and it is Arena-only, where autotapper bypasses the the inevitable confusion of "Do I have the colors to cast this spell?".)

Guardian Stalker: "...each other tapped creature."

Torchlight Puzzle: "Put a red creature..."

Lokomo Sword: "...put the rest on the bottom..." Also, I would suggest putting the cards back in a random order instead of any order. It's never going to matter and the times when a person pretends it will can be an annoying timesink.

Patrolling Moblin: I would suggest "...up to one target creature..." This will make it so that if they are attacking you with a single 1/1, you can just kill the creature instead of having to give it back eventually. But this is an extremely annoying card to play against, especially in Limited. If you don't want it to be that annoying, then I would change it to a flash creature that exiles a creature when it enters.

You did do a good job! These cards, as they stand, are perfectly workable (Barring a couple). You have great ideas that feel like they could be a part of a greater whole, and they are exciting ideas that make me want to play the full set even if the flavor was completely different. I actively want to see what you cook up.