Also, by my basic math we will possibly have about 4,700 pilots in 2023. Maybe a bit more as we staff more pilots per 320 than E90 due to the overnight flying.

I think you are counting the E90 future deliveries, which probably won't happen. If they do, most likely they will replace older E90s. I doubt they grow the E90 fleet count from where it is now. But it is possible of course.