Sharing Rooms

I currently have a 23 month old and baby on the way. They will be 26 months apart. We live in a 3 bedroom home but unfortunately, my husbands grandmother needs to move in with us. It happened very suddenly, and I only have this week to prepare... I have never been for the idea of my kids sharing a bedroom. I don’t see how it works. I know the newborn will be with me in my room for a little while. But I want to know opinions on this. I fear for the added furniture in my 2 year olds room because of the potential hazards (I can not secure furniture to walls.) I also don’t know how it works with them being at totally different sleep stages. My other option is to have grandma and newborn sharing the room mainly for furniture/changing purposes. Newborn will sleep in my room with the exception of naps once he outgrows his bassinet.