DeKnight bringing a composer he is familiar with into the sequel is not an uncommon practice for directors to take.
With the film just over a year away from hitting theaters, there is plenty of time for Legendary to promote the film and get these plot details out in the open.
For the time being, they are likely trying to keep those under wraps until filming has been completed.
Not much about the film’s plot has so far surfaced, but recent set photos showed Boyega in a newly designed Jaeger pilot suit.