The bedroom thing.
My Dad moved into a two bedroom house with his dw and her son, my db shared the room with stepbrother and I was put on a camp bed in my dad and stepmum so bedroom.
We went from having a bedroom and every weekend with Dad as he lived in same town, to once or twice a month. I hated it, they'd make Complain about setting the camp bed up, arguing about whose turn it is, faffing around trying to find bedding, teamed with the reduced contact I felt like I was an annoyance to them both, and the fact they hadn't thought to set my bed up before I got there, or sort clean bedding in advance reinforced that he didn't really think about us much. Out of sight, out of mind.
A few times I complained about lack of privacy, I'll never forget when I was 12 and had my period, I woke on the morning knowing I'd leaked, stepmum wanted me to leave the bedroom so she could get dressed, I asked if she could use the bathroom instead and was bollocked by Dad for being rude, it's her home not mine, I should do what she says, when I said I was reluctant to get out of the camp bed, dad told me to stop being ridiculous and stepmum sighed at having extra laundry.
Any complaints about seeing him a lot less he'd say that he has to travel half an hour each way and it's too much to expect him to do it every week as he needs to spend time with his wife.
Tbf, it wasn't just the bedroom thing that Dad allowed us to be treated so differently on though so maybe that made the bedroom thing feel worse than pps suggest is reasonable? I felt very much like an unwanted guest rather than equal to my stepbrother though and when I became a stepmum I didn't want dss feeling like that and would have permanently set up our second living room as a bedroom if needed, he had his own place by the time dd was ready for her own room so wasn't an issue for us in the end.
Your adult DC will prob be thinking of moving with their partners or just renting their own place so they coukd their own room soon anyway? I think I'd ask the adults not to have their partners staying over the few nights a month the dsc are there, just to reduce the amount of people there at one time, if you have seven adults and two DC sounds squished and I'd be stressed as fuck :)