I would go with Sony just cause I hear they have the best picture. I never use the operating system on my LG and Samsung since I have an Apple TV . TV operating systems are horrifying to deal with. I say this because the Sony operating system is limited as far as getting apps and so forth as I recall.
If there's enough room for the main speakers on the side of the TV then the 65 inch would be worthwhile pursuing. 75 inch TVs would be nice but they are seriously heavy versus 65 inch which is considerably lighter. The 65 inch requires two people where is the 55 inch can be handled with one person if there in good shape.
I use Bowers and Wilkins and maybe I would be better with Sonus faber.
Since you're really invested in a really good decision I would post a picture of the room since people really taking an interest in this. I don't post pictures and maybe I will at some point but I have to rearrange some things to make it all look pretty it's hard for me to do it.