Way Deeper Down: Ideas for the mod?

Hi! I'm currently working on a mod about caves... Yeah, that's very unoriginal, but this not the common cavemod! This one is not just minerals, they are underground biomes, depending on the height, because this mod divides Minecraft in layers! It has some dimensions too. Here are the things on the mod

Dimensions:

Svartalfheim

Core of earth

Biomes (core of earth)

The corelands: forest with new trees, grass, type of wood and food (The core-lemons)

Fungi Foundi: mushroom biome with moss and mossrhooms, also has moss-moo (the mooshrooms of the biome) and mushquitos (mosquitos that attack only one time and, if bitten by crystal rat, freeze. They absorb the blood of victims)

Porcini Bay: mushroom biome with new mushroom and animal (porcini pig). Also it has a lot of mushroom mobs that would love to consume your flesh

The hot caves: also being deep in the overworld, is the normal biome, most common

The crystal forest: obviously, a place full of crystals. They can be diamond, lapis, cinnabar (curative stone), quartz, rose quartz and emerald, and also pillars of crystal, where appear some crystal rats. In this biome, as in the overworld, appear cinnabar skeletons.

Cave Biomes

The hot caves: in the overworld, this biome has all vanilla ones and also mercury, cinnabar and quartz in big proportions. Anyways, is dangerous to wander around there, because you won't see anything 4 blocks away from you, a lot of things are poisonous and there are some mobs that won't let you escape.

Jungle caves: having moss hanging on the ceiling and leaves around the floor, the jungle cave biome is the one with most vegetation, and for that reason the dracaena plants are growing there. With some bonemeal, that plant can become a gorgeous tree, that also will give you lots of money as well as a new type of wood. But be careful, there are other plants waiting, as bomb plants and corpse flowers!

Swamp caves: Like humidity? You love to take a bath in fresh water? Worry no more! The swamp caves are bringing underground lakes! Be careful, they might be beautiful with all the waterlits (plant) and glowing shrimps in the water. Piranhas are not that beautiful though.

Other mobs:

Worms: they just wander around. If walking on a crop, it grows faster. If hurted and there is dirt below, it will escape underground.

Dwarfs: you can give them diamonds and they will go mining for you. Also they turn to stone when in contact with sunlight

Rats: can be tamed by cheese. Attacks in group.

Ant: they will appear near an anthill. If they find an item, they will carry it. If the anthill is broken, it will drop a queen ant

Champ Champ: mob found on mushroom biomes or caves. Can be of different species, depending on the biome. They are basically mushrooms with legs that on their "heads" have mouths

Fungi Flight: a flying mushroom that shoots exploding spores to the floor

Hobs: also coming from Nordic mythology the hobs are small creatures that live underground. They would be smaller than the dwarfs, and instead of living in a town, they live in holes

Crawlers: they exist in four biomes. They are a bit weird, but they are neutral and can be ridden.

Foot Swallowers: they exist in three biomes. If a player is stepping on them, they will begin swallowing it slowly.

Bosses:

Marabunta: if you take human blood from the bag of a mushquito and craft it with a queen ant, you'll get a bloody queen. If you right-click an anthill with it, the Marabunta will be summoned. Marabunta is a giant ant made of small ants. It shoots acid, summons small ants to attack you and has a lot of life. If you kill it, you'll get the totem of the queen, that works as the undying totem, but gives you an effect called "rage of the Marabunta"

Temple Master: An alive structure that only can be killed by successfuly breaking the Temple Hearth, found inside this boss. It will drop a Temple Hand, which can shoot rocks.

The Massivehroom: a giant mushroom that shoots spores at the player and sometimes to the floor, spawning then some Champ Champs. It will drop a lot of mushrooms, a spore shooter and, if you are lucky, an helishroom! (Thanks for the ideas Ooooscar!)

Quartz wither: with the head of a wither skeleton, a quartz wither skeleton, and a rose quartz wither skeleton, with the normal 4 soul sand blocks you will summon the quartz wither. A really easy boss to kill, drops the quartz star, that if used on a beacon will make a quartz beacon, useful in multiplayer to don't lose each other.

Crystal Crab: a giant crab found in the crystal forest. Will protect itself with its shell and bounce on walls. It drops material used for magic-properties-blocks and a special pickaxe to mine carbon, the new ore that can become diamond with a bit of luck.

The Sludge: A big slime that can be summoned on swamps. It has water powers, and might shoot lilypads at you. Also be careful when he jumps, you never know where it could land...

Effects:

Toxic: when grabbing, standing or bathing on mercury, you'll get toxic, a mix of bad effects.

Antidote: prevents the toxic effect

Rage of the Marabunta: gives speed 2, resistance 2 and strength 1, perfect for an emergency escape

Darkness: makes you don't see far away, but you see fine in close distances. Also you hear strange noises.

Parasite mushroom: a type of poison able to kill, but also easy to cure with milk or shears. It will drop special mushrooms when sheared

Cinnabar bones: cures whoever has this effect, but it does it in a way that could be dangerous when escaping. Is cheaper than a real health potion, though.

Bad smell: Will give bad effects such as slowness and fatigue. Not armful at all.

Enchantments and curses:

Blessing of the Immune: can be used on mercury stuff. Will change the toxic effect for an antidote one whenever the player is wearing/using something enchanted with this.

Bane of Mushrooms: makes extra damage to every mushroom-related mob

Curse of the First Law: when holding a pickaxe with this curse, blocks below the player will start to break extremely fast... You know what they say, don't mine straight down!

Thanks! Any idea would be appreciated. Maybe a new mob or boss would be great.

Also, the main idea is to make the caves of overworld be the same or maybe just similar to the biome on them, and hopefully make a boss for all of them.