OP,
Girls tend to like to bring their friends up to their bedrooms to show them their space.
Even more so as teens.
Going into your bedroom is not on and you need to be crystal clear on that point.
There shouldn't need to be a lock on your bedroom door.
I wouldn't hesitate to tell the children that they are NOT allowed into MY room.
At 8 for bouncing on sofas and beds, utterly ridiculous and very rude.
I would be noting the names involved, that is bratty behaviour and no child EVER did that here and there have been many dozens of children here in the past 20 years.
YOU set the tone for what is acceptable in your home.
Remind your daughter in front of the children, absolutely no entry into my bedroom.
Children are curious, but the getting into your bed is too much.
We have a large older house and hide and seek was the children's favourite game, as there were so many places to hide.
I admit it used to absolutely do my head in, but I sucked it up as they all loved it so much.
Seems so long ago now.
The years go so fast, they don't play games for long.