Scottish adopter and C&F social worker.
The children will still have looked after status at the moment, the children’s hearing will most likely be to either continue the supervision order or to change the condition of residence (eg to your address) on the existing supervision order.
It’s usual for the children to be attend the children’s hearing - it’s highly unlikely they’ve never been to one - I’ve seen babes in arms brought to hearings before now and the Children’s Reporter can compel them to attend. Depending on your local authority it may be possible to have them excused, but it’s entirely at the discretion of the Reporters Administration. You may also ask for the hearing to be postponed to allow the kids to settle into school - which may nit be possible if the supervision order needs renewed.
On a separate note, I’d seriously question the wisdom of putting them into school 3 weeks into placement - ours were placed over summer and started after the September weekend break, which was considered quick. Depending on ages it would be worth keeping them home for longer, especially if it’s a source of fear for them.
In saying that, the hearing itself should be relatively straightforward, the hearing invitation should tell you the purpose of the hearing.
Things I’d be checking are whether birth parents have been invited - unless the DC have been placed with you on a POA, the birth parents will retain parental rights and should be invited. If that is the case they should make appropriate arrangements for the DC/you/birth parents. I’d also check that your address etc will be kept confidential, not included in the supervision order etc. I’m surprised no one talked about the Hearing system to you given it’s the legal process for looked after children in Scotland, but have a chat with the DC social worker on Monday - it’s a routine part of the process.