Since you are staying at CBR and HS is so close I would take a bus there. The boat launch is right next to the bus stop, so you’ll avoid having to cut through the park (waiting in bag search and turnstile lines). Take the boat to BW, walk or boat to Epcot for illuminations, then take the bus back to CBR from there.
That my sound the most efficient, but if I were you I would just hop on whatever bus comes first at the bus stop, Epcot or HS. Either way it sounds like a great night!