It depends what kind of report the Court orders CAFCASS to write. A full report (Section 7, I think) often (but not always) involves people other than parents, so you might be visited and interviewed whereas a wishes and feelings report involves a short interview with the DCs and each parent.
Age doesn't seem to be that much of a factor as to which report is ordered in my experience - my DSS was six when the court ordered a wishes and feelings report; despite DP's solicitors objections.
Anyone know much about CAFCASS and who they are likely to interview. Have looked at their website put step parents and step siblings are not mentioned. DH Ex has stooped to lower level than we could have thought and currently she has no contact with DSC. But DH thinks will get to court case eventually and I am wondering what CAFCASS do. He dealt with them when got divorced, but in my divorce, arrangements for my children were sorted without need for CAFCASS and TBH I am really worried about whole prospect. Will I be involved in it all as DSC lives with me and DH? and will my own DC be involved in interviews etc? I know it is important due to DSC?s safety etc but the whole thing worries me. Any advice greatly appreciated.