I really like the idea of oscars and the blood oscars look amazing when colored up. However, I think adding the the number you are looking at is heading for a problem down the road unless you have an enormous filter.
Oscars are messy AF. Those tinfoils barbs and balas not only get large but crap all day long. The acaras do not help to ease the bioload.
A year and a bit down the line with good husbandry, you are looking at anywhere between 12-16 12" fish. That is enough poop for a small house dog. lol.
If I may, i would suggest lowering numbers of oscars to maybe 4. That will still leave you with 12 good sized fish in 350gal. That isn't even including the acaras. This may also make the oscars stand out more as they are not in a sea of red.
just my 2c