Personally I would go for some bookshelf speakers. That will give a better surround presentation and allow you to add overhead speakers for Atmos/dtsx in the future. If you add rear and side surrounds now, and want to add a bed layer, the overhead speakers will be in the wrong place. Is there a main driving factor to put all the surrounds in the ceiling? FWIW, I have a pair of rc85i’s in a side room and they are pretty good.
I would also take a serious look at replacing the 505. I also have experience with that, and there are a lot of subwoofers out there that are in a completely different league.