You cannot get wrapped up on what day of the week things happen. No one knows and even those that offer opinions are not sitting in admissions and they are just opinions. This type of information is not released even to FFRs.
It is impossible to have a set day to receive BFEs. I would also assume that it changes as the process goes by. Once the application window closes, they have more files to review so more reviews are required.
Here is what we do know. The application period is still open and if you are on a competitive slate, it will be a few more weeks until they can be resolved. Once the application window closes, admissions works to resolve the slates. This is why they say the majority of appointments happen in March.
The admission's board does not meet and say "yes/no' like a normal college. They qualify your file and send you back to admissions so you can compete on your nomination slates. The slate cannot be resolved until all applications are completed.
In terms of rejection letters, they also go out all the time but just like BFEs, the majority will happen after the slates are resolved.