Half No, You can not straighten a dolls hair with a straightening iron but you can boil wash it straight.
Yes you can wash it but you will have to use a conditioner on it otherwise you will not be able to brush it.
Baby soap
yes i wash mine all the time
Yes, but don't get it in there head or it will rot
NO! this will ruin your dolls hair if you really have to send her to the doll hospital where they can take care of her hair and she will be as good as new
Dolls hair can't grow.
You could brush it with a soft newborn baby hair brush to keep it knot free but don't wash it because that might damage it.
No it will destroy the dolls hair, maybe make it fall out
A dolls hair does not grow because it is plastic. If you are a scientist and bring it to life then maybe.
then why do u wash your hair?
Yes