Hello J., I want you to know that your question as serious as it is made me smile and go down memory laneaabit. In fact I will call ech child and laugh about someof thier experiances later to night.
I am the elsdest of 10 children. I have 5 children and have had several foster children that I am proud of. To say the least there was alot of shareing of rooms.
I was going thru a cleaning phase and actually had furniture out of rooms to paint ans such... and came back home from an errand to discover that mu eldest children had taken over the biggest room( mine ofcourse) and had set up the bunkbeds and had moved the crib in there.. Why since they had rooms --becasue they wanted to be together and liked to see the baby and have him talk tothem. They were also the ones that taught him how to get out of the crib so he would crawl into bed with them. So it sure won't hurt anything and may make great and strong bonds between them.
I have a group of friends that are Samoan, and they sometimes have all the family in one room just so they can talk to one another til they fall asleep.
Before the modern age just about everyone had 2-3 children in a room.
They will learn to adjust and to be quite for one another. Also my children have learned from an early age to sleep through just about any noise that comes along that doesn't apply to them including crying baby, and siblings that sleep at different times... Good Luck