One thing that has always been an issue for us is that we only have one bathroom.
When it comes to everyone needing to get ready at the same time... to say that it is not easy is an understatement...
So! I pull all of the hair and make up products out of the bathroom and put them in a basket in the living room. This clears out the bathroom for showers, brushing teeth, and potty breaks.
The living room is the largest room in the house so it isn't crowded and the kids can watch a show while they wait in line to get their hair fixed!