The section regarding those already in the hold pool does seem rather ambiguous.
The last I heard from those in the know at BA was the hold pool was the correct size and all those in it plus a few extra would get start dates 'in due course'.
I would interprete the email as confirming that plan, they seem to be 'pausing' recruitment as anymore pilots in the hold pool would mean some never getting a call before falling out.
I'm still expecting an extended wait though, anyone have a rough idea about how many are actually in the pool?