I am not surprised you describe ddyounger as a really good person, blessed. I have no doubt of it.
I would say dd17 here is empathetic, kind and concerned about others. But she runs from her room. She hopes to open and close the door quickly so that no one criticizes. She can go into denial about it. She insists one problem is not enough storage space in the closet, and this may be true. But the remedy for that is to physically reach the closet to discover what's wrong, and she tends to put up roadblocks to doing that. Always in a rush, she will shed clothes in desperation to tug on the next clothes and make a deadline, leaving things lying, forgetting where they were in the room. I have heard clothes hangars crack underfoot, because they were fallen under a piece of clothing, lost.
Ds31 overcame this by regular purging - ruthlessly tossing items even if it hurt. This was not ideal, but it did get him out of the messy room habit. It was just something he did, alone, and he really kept me out of it. I know that he was my child who was most influenced by peer pressure - maybe he was embarrassed in front of some friend.
Dd36 overcame it, I think, because of learned organizational ability, needed for school, to compete for high grades. She began at some point treating her room the way she treated her schoolwork, and from then on there was no problem.
I didn't rear dstepson38, but I know about him that he never had the problem, even though his childhood life with his mother was turbulent and she lost custody. He ended up living with HRH, a sidetrackable, non-demanding person, full time by middle school and even then never took on sidetrackable habits. So I'm going to say this is very much related to inherited tendency. He seems most like his mother's sister to me - loves order like she always has (I knew her in school).
Maybe my late dh was a better type of Dad image in the household than HRH is. When my late dh would drive into the driveway, ds and dd would scatter, racing to do whatever chore he had mentioned before leaving. He was a tough Dad with high expectations, and HRH has always been more willing to listen to excuses and be protective, even protecting from his own rules.