I believe that the Bijuus will remain separate because their individual personalities and names are significant.
We know that the bijuus will no longer be enslaved and obviously ninja will no longer be forced to become jinchuriki.
However Ninja and Bijuu are strongest together so this is what I believe will happen. I think that Ninja and bijuu will be allowed to chose each other. This way, jinchuriki will still exist, but Ninja and Bijuu will cooperate together to create the strongest possible combination.
We know that the bijuus will no longer be enslaved and obviously ninja will no longer be forced to become jinchuriki.
However Ninja and Bijuu are strongest together so this is what I believe will happen. I think that Ninja and bijuu will be allowed to chose each other. This way, jinchuriki will still exist, but Ninja and Bijuu will cooperate together to create the strongest possible combination.