She cried from fright and since then all i have to do is a firm no and she backs off.

I read that if you bring them close to you they have to suck not drag and bite.

Biting siblings if a different issue.  He sure is starting early.  Ty my oldest picked this up at daycare.  I'm sure he was past 2 years old.  He bit be on the leg once.  I bit him back and he did try again and I warned him I'd get him back.  I said remember it hurts.  It's not nice.  That nibbed it in the bud.  He never did it again.  Even when he came home with more bite marks at daycare. 

Because of the age he may not understand even a light bite back.  Maybe if he sees you sad  and say mummy is sad when you bit your brother/ sister.  Say sorry and hug and say this makes mummy happy.

Hope this is of help.

O

my brother was autistic ,and he used to bite people. after a year or two we ended up curing this habit by biting him gently back, and he stopped quickly, buti would only use this at an absolute last resort.