From my experience, the places to be avoided in Shankill are -
Cromlech, Rathsallagh and Shanganagh Cliffs. The older parts of Shankill are fine e.g. the village, Quinn's Road, Woodbrook, Dorney Court etc. Bayview is nice but it is very close to Cromlech and Rathsallagh and if you have kids, you'd want to watch it. Do NOT go near anywhere close to the Dart station as long as it is on the other side of Corbawn Lane or at Eaton Wood. Shanganagh Cliffs and Rathsallagh are both big no-nos
As regards Ballybrack, Wyattville is fine. However, I would avoid most other places as they are rough. The only other exception for me would be houses on the same side as Applegreen service station in Ballybrack village. In and around the Tesco is not great either