Do you use the fireplace? You can probably fit 3 identical towers under it or evenly around the room if you use it , as far as surrounds place them somewhere your more comfortable with . S35 is too tiny I wouldn’t bother a passive soundbar is better .
Get a front view of the TV, I’m shocked a massive room like that has Bose speakers but there so popular due to tiny size in non audiophiles I’m not surprised...
go for largest speakers you can fit .... going to need some serious subs too . Polk which model? Could be a temporary fix
I’ve used towers as surrounds to successfully, on bookshelve speakers stands . But bookshelves may be fine ...
Small speakers are terrible for that room ... go big or go home 🏡..
I’ve seen smaller movie theaters 🎭 ...then that room.