Pinkl1mo
Name: Flarepaw
Cool
Appearance: ginger like fire with green eye and lighter ginger paws (no scars)
Is that how she gets her name?
Gender: she-cat
Okay
Rank: hunting apprentice
Is this a rank where you just train to be a hunter? Could make is specific (I hope I spelt that right lol)
Age: she-cat
Right, she-cats are needed.
Clan: Pierclan (Riverclan equivalent but on a ocean)
Ooo your own made up, clan love it.
Personality: she's extremely energetic, silly and like to forget about job for butterfly, but she also is extremely protective and never wants to see her family die. When grieving she often lashes out and is know to stay from other at all cost when mad.
Needs more bad traits and good to even it out.
Kin:
Mother: Redsky- a red she-cat with green eyes a white tail
I love her name and I'm guessing her pelt is how she got it. But are cats red or is that like a orange or what are you talking about? More description too would be nice
Father: nobody knows
How can nobody know. What about Redsky she doesn't even know who she had kits with.
Foster mother: Brightsky- a exacted replica of her sister except lighter colour (it's freaky)
I would describe Brightsky with the same detail as her sister but with a lighter coat. Also I have a oc names Brightsky.
Brother: Foxkit- a dark ginger Tom
More description would be nice.
Sister: Creamkit- a cream she-cat
Same here needs more description then just fur colour.
Foster siblings/ younger cousins
Alrighty
Blazepaw- a ginger tabby Tom
Description
Creampaw- a similar cat to her deceased cousin but with a white muzzle
You have to describe Creampaw not just say she looked like Creamkit and you probably want to add in Creamkit's description that's he's dead.
Turtlepaw- no one understands but she a tortoiseshell she-cat.
Why doesn't no one understand and I'm guessing they know what turtles are because they live near/at the sea?
Mate: none
Wells she an apprentice so yeah
Mentor: Seabird- agree she-cat with blue eyes (formally known as Dovelight but an accident made him change it)
Better description. Instead of saying an accident say what the accident is.
Apprentice: none
Well of course she doesn't have one.
Backstory:
When she was half moon old opened her eyes to find her litter mates were sick and she was the first she was suffering the worst but yet soon it changed to Foxkit who died at 3 quarters moon Creamkit died at one moon and a Flarekit slowly recovered.
This is all very confusing, it need commons etc. and just how you've worded as made me confuse. So
you'll  need to fix that up.
When she was two moons old a fox broke into camp and attacked the nursery. Brightsky went into labor during all the drama Redsky died, the fox panting hard and about to run when a Flarekit latched onto its leg giving Iceflame (the deputy) enough time to kill it.
How is a kit brave enough to latch itself onto a foxes leg? And giving the deputy enough time to kill it? How strong is this deputy to be able to kill a fox by himself.
Brightsky let her name one of the kits and Flarekit helped name Blazedkit.
That's nice of her.
Others began questioning her and she and Blazekit came up with a way to prove them wrong.
This makes no sense. Why were "others" questioning then and what does "her and she and Blazekit"? I think here you'll need to make it more clear and tell the reader who is her and she.
They even made up sign language.
Wouldn't they question them more with their own language?
Everyone decided it would be best to delay her apprenticeship.
Who is everyone and is this talking about Blazekit? You'll need to be more specific.
When they became apprentices all five kits at once everyone evened out but bettlestar and Dewdusk (the med cat) candy help but notice things are changing with the clan and the prophecy still lingers between them.
That first part of the sentence makes no sense to me and who is the prophecy lingering between? To you mean the leader and medicine cat or Flarepaw and the medicine cat?
Especially that the tongue less kit is training right now with the four foster litter mates to guid her.
Tongue less kit?

Other: she is mute and has a prophecy that hasn't come into full place yet.
Mute? Okay that's a bit hard to believe.

Flarepaw is a great OC but there a heaps of things you can fix up on. Personality needs more bad traits, more description for your cats appearances and your backstory us all over the place and I personally didn't know what was happening and because of that I was confused everything else to me seems fine. Just follow what I've rated and given you if you like and Flarepaw should be a lot better. I would rate Flarepaw a 6/10 any questions ask and I'm so sorry for the horribly long time it took to rate.