I wonder if there's any restrictions on which voicebanks can use the new English feature. Like, we see Sasara can and I see no reason why it wouldn't work for Yukari, ONE, or the Tohoku Sisters, and then there's the musical isotope series. Kafu is already alpha-locked so I can't be sure.
Also this means Flower English is finally happening in some capacity, so much for those who complain about English Flower producers XD