Eldest two get their own rooms. Youngest two share. When 16yo goes to college etc, three remaining each have a room

I'd put the 16 yo in her own room because she needs space most. Hopefully she can move out at 18 and the boy can have his own room.

I’ve been there and done that with my family. My parents split the eldest two (two sisters) in one room and my brother and I (the youngest) in another room. When we got older and lived in another three bedroom home, all of us girls were in one room (I was 13, my sisters were 16 and 18) and my brother got his own room (he was 14-15). He then started using the shed as his room so he could party with friends, and then our mom brought in a homeless lady to take his room for a few weeks, or months.

Oldest and youngest in one room, as the other 2 are the closest in age and same gender. Rig the bunkbed in the 16/6 room with blackout curtains so her later/earlier hours don't wake him.

6/8 together, 10/16 together. When 16 moves out, split by gender.

16 yr old gets their own room, middle two get their own room, boy gets the smallest room, and the parents get the dining room or living room turned into a bedroom.

I had 2 boys and one girl (middle child). All 3 shared a room in a two bedroom house until the oldest was 10. We moved into a 3 bedroom. My daughter got her own room and the boys shared. When my eldest started high school we made him a room in the garage with temporary, insulated walls and added a ceiling vent for air conditioning and heat. After my eldest left home his room was taken down. If you have a garage, perhaps you could do something similar for either the youngest or oldest.

Adults in one of the 2 regular bedrooms and Give the largest primary room to the 3 girls and the smallest room to the son. 2 girls can move into regular sized room and give you the primary when the oldest moves out.

You need to find a way to create more space or an additional bedroom. 16 & 10 in one room which really isn’t ideal. And 6 & 8 in the other room which also isn’t ideal. Then when the 16yo moves out at 18, the two girls left share a room and the son gets his own. Finding a space or a way for the teen to have some privacy and keeping her belongings safe from little hands is super important.

16 yr old gets own room (teen privacy and largest age gap), son gets own room (boy privacy) , 8&10 get own room .. wait where will you sleep?😅