I have no real insight into the hiring situation, but did fly with someone from recruitment who told me they had interviewed and hired some six hundred pilots already this year and all class dates were filled through the end of the year.
Most likely the above information about April class dates is correct, however things change quickly.......they may give a class to someone who has been swimming in the pool for 6 months and find out they have already went elsewhere. We had a similar situation 3 years ago when the talent pool was started and I hadn't had any news or update for 6 months and then out of the blue an email with a class date in 2 weeks.