should king ghidorah, mothra and, rodan get new abilities?

Rodan: keep it simple, just a Sonic Boom attack, maybe a Fireball attack (as a nod to Fire Rodan) and possibly a Sonic Screech attack that creates a fissure.

Mothra: make her a man-made MUTO (the caterpillar Monarch looted from Ford's home and conducted nuclear tests on), give her Regeneration, ability to use up to 80% of her brainpower, magnetism-inducting seismic wingspan allowing her to create strong gusts of wind (which she could use against a batch of fighter jets, knocking them into eachother), or even hurricanes, Acid/Spore attack, poisonous stinger, maybe beams of some kind.

As for Ghidorah, since he's from outer space (or at least was in space at one point depending on how they do his origin), I was just thinking: why not give him Cosmic Energy Beams like Galactus has? I could see it now: when Godzilla is fighting Ghidorah for the first time, the military hits him with an EMP weapon to try and help Godzilla, then Godzilla puts a pounding on Ghidorah, who can no longer use his Gravity Beams, only for him to show off his new Cosmic Energy Beams, which would theoretically be immune to EMP, since it's basically energy he sucked from other planets and not electricity-induced, I could be wrong, though.

Another new attack I thought of for him: Hydra Beams. Since, in my origin idea, he would be the combination of 3 Hydras merged together, I thought of another special beam attack that injects oxidizing Hydra venom into its target's bloodstream through a crystalis structure it forges on his body. This causes him to grow increasingly unstable as his Dopamine levels continuously drop as his oxidation levels rise. When it reaches 100%, it pretty much kills the target because, as anyone with any kind of scientific knowledge knows, when your Dopamine hits 0, you're done. Just think: he could use this on Godzilla so we can get a rogue Godzilla that actually attacks the military, civilians and buildings intentionally in the sequel, forcing them to unleash Mothra in an attempt to save him, and force them to closely monitor both monsters at once while they're going on a tear. You could even have his body grow more and more frail as he inches closer to death, basically a nod to BG (Hydra Godzilla?) in the sequel.

Which brings me to Godzilla: during this time, you could give him a ball of Hydric Acid as an attack. Also, just for effect: you could have it infect one of the nearby civilians, who somehow survives, and if you really want to get technical about it, from there, you could then have an emotional scene where nurse Elle is forced to put him down in front of his watching wife's eyes against her will, and we get a nice glimpse of the horrified look on both their faces.

Not to be mean but I don't like a single new ability that you gave the monsters @KMANX89

I rather have Rodan rely on his speed to out speed his enemies and grabbing them and throwing them like the male Muto did to Godzilla. Possibly Rodan could absorb too much radiation and get a sniper rifle like radiation beam. Mothra should rely on her poison scales, stinger, and her silk. King Ghidorah should have his electric beams (though they might just be plasma), brute strength, flying, and the ability to shock enemies with electricity by physical contact.

I'd say.....

Rodan keeps sonic booms around, and maybe a screech attack to make for a possible lack of an energy-based range attack.

Mothra has poisonous scales again, and perhaps sonic booms as well. Perhaps even poison storms of scales.

Ghidorah should keep some form of his old gravity beams, but in a different format that still resembles their electrical nature, as well as energy-siphoning bites.

Godzilla of course retains the plasma breath, but I'd say that he should gain a nw attack to even the odds agains King Ghidorah: a little lesson learned from the MUTOs by concentrating his stored electrical energy into a short-ranged pulse.

Ugh, can we please stop wanting to make Mothra a M.U.T.O.? The M.U.T.O.s were created only for the 2014 movie because Legendary didn't purchase the rights to any other monsters. I liked the M.U.T.O.s, and I would love to see them return in comic books or video games, but Legendary is done with them. Mothra looks nothing like the M.U.T.O.s and should have no relationship with them at all. She should simply be a giant moth. Plain and simple. She doesn't need to be a goddess or anything, but making her man-made would spit in the face of all of her origins. She is a mysterious being that some worship as a goddess. At least make her a creature with unknown origins that is worshipped by a cult on a remote island. I personally hate the idea of making her either mutated from the cocoon in Godzilla 2014 or somehow related to the M.U.T.O.s. Sorry if I am raging, but I wanted to put my two cents in.

@Mecha Rodan: why no regeneration for Mothra? It compensates for her lack of durability. Since she's a moth, that obviously gives her low stamina, as in, unable to take a lot of damage.

Also, little food for thought: any thinking military out in the open would hit Ghidorah with an EMP weapon to give Godzilla, Mothra and/or Rodan a fighting chance against him, what then? A lot of good his gravity beams and shock by contact ability would do him in that instance. The Cosmic Energy blasts would be his Plan B in said scenario, and it makes sense for him coming from outer space (even if he didn't originate there) and absorbing energy from all them planets he destroyed, just like Godzilla's nuclear radiation gives him his Atomic Breath ability. Also, Grand Ghidorah had mind-controlling powers, too, in Rebirth of Mothra III except this does it in a way that's scientifically feasible as I layed out while eventually killing him, adding yet another layer of dangerousness to him.

The King of the Monsters,

I hear yeah man. The MUTO do not need to be the defining enemies of Godzilla and I think they should be left alone from here on out. Any further mention of them should be regulated to remembering the events in the first movie. That's it.

^Another good point, they served their purpose and like bryan cranston, they are done with.

^More of em theoretically could show up (actual MUTO, with different designs and whatnot), but I get what you're saying, I guess the right choice of words there would be man-made kaiju, and not even from scratch, they could use the caterpillar that they looted from Ford's fish tank at his old house and mutate her with nuclear tests and whatnot.