Conversation so far:
How do celluloid records have anything to do with Laswell?
Laswell became the de facto house producer for Celluloid until the sale of the label in the later 1980s.
Where were they located?
Within a few years of moving to New York, Laswell founded a recording studio.
Was there anyone else involved in the label with him?
with producer/engineer Martin Bisi (of later indie rock renown) and hooked up with Jean Karakos and his fledgling label Celluloid Records.
Did any other artists record under that label, too?
now also a production unit consisting of Laswell and Beinhorn - Maher being long gone - and by 1984 consisting solely of Laswell.

Question: Why style of music did it predominately record?
Self-contained rewrite: Why style of music did Laswell from Celluloid Records predominately record?