This still feels too good to be true, and I'm trying to figure out when the other shoe will drop. Especially the 10F CR5... what a seemingly impossible passenger-friendly improvement from CR7s or CR2s. But hey, maybe just this once, it's untarnished good news
On the "squeezing" front, DL manages 12F 319s and 16F 320s with 6 and 10 more seats than the stated UA seatcounts respectively, so I'm sure UA can find room. Admittedly, the DL aircraft do this with 3 rows of 34" C+, 36" in F, and the double-slimlined lavs in the back.