Yes, all lake view rooms should be able to see the fireworks. They pipe in the music to the beach and the TTC, so you might be able to hear it. I don't believe they play the music through the television like they do at BLT.
PVB studios have a queen bed, queen sleeper sofa, and twin murphy bed. There would be no room for a roll-away bed. Regardless, no DVC property will provide an additional sleeping surface.