I think I need to say something's. I know I'm not the best with advice, but just let me try. Understand you don't have to actually read it if you don't like it. Also, if you have an actual good argument or idea then bring it up. You know I can be wrong and not scared. Plus it's a learning experience for me and will help me out if I offer any advice to others in the future.
Ok enough with that let me explain something's.
Child ghost oc's in the Creepypasta fandom
For child ghost please explain why they had to die, why their still around, and why they harm others. I get the whole, "OH! they died young, so of course unfinished business." Sadly that's over used and needs a little more added on to. Maybe they stay around beacuse they want justice, or to care and make sure a love one is safe, or their very attached to an object, you know a little more then just, dying young.
Parents killing kids ((know I'm going to get hate for bringing this up))
I don't like it, I'm sorry. It's kind of sickening to me for parents of a civilized society to just kill their own creation. I can see something like that in like 1900's or lower, but nowadays not really. Plus it's usually the same reason... Like the parents being depressed and just go on a abusive rampage, or the parents just don't want the child and axe them off. You see mothers, fathers, and other types of care takers have an emotional connection ((most not all)) towards said child, so they usually don't want them to get hurt. Hell most parents would want to hurt themselves, then hurt their own child.
Now to turned this around round and if your gonna use this then think of a original spin. You know like the mother, father, and or caretaker is loving, but suffered some hard times, so to deal with is start taking narcotics to just deal with the pain. Plus the narcotics made them happy, so they just kept it up after everything got better. Sadly, they never truly experienced a exterm, terrifying high before, that they accidentally harm or kill their child. ((Look it up it truly happens)) plus with this type of idea you can add on what they took to cause such a terrible outcome. ((This is just one idea))
Its alright to explain how the child died by it being wrong place at the wrong time. It's sad, and horrible, but happens everyday in our great world.
Personalities shouldn't be too complex because their a child and don't really have much of a complex brain. Also, as a ghost/spirit their not going to be enjoying it though. Their mostly going to be very confused, scared, angry, etc...
Relationship as a child ghost/spirit should be a no. Think of it you wouldn't want your 5 year old son or daughter making out with another kid. Plus when their childeren they don't feel love for each other like that. Ages 12 and up are alright ages to start because emotions like that sort of start to form. No sexual though! That's just sick guys. Even darwing perverted stuff at age 16 is questionable. ((I know 16 is teen, but it's just an example))
Alive child Creepypasta oc's
It doesn't really work out at all. It's hard to write a child killer alive in my opinion because them being a flesh eater is stupid, super genius is so unrealistic, I don't like the whole zombie idea because again unrealistic, childeren are usually not killers because they are weak. Not being rude but you can just kick the shit out of a child coming at you crazy. Not saying in reality you should, but it's true. Don't say, "Oh! Their a demon, so they can kill at a child's age!"
If you find a way avoid things like, being taken in by Slenderman, being a child of a "cannon character" like Zalgo, and just being super powered as hell. It's just so stupid and uncreative in my opinion, sorry.
Thats hats all I have to say. Add in stuff that I forget, or what you think in the comments.