Do I need a header when non bearing wall
If it were me, I would use 2- 1 3/4'x5 1/2' LVLs. They shrink very little, hold up more than you will ever need for the dead load of the wall. The crown is attached to the wall, but it should be attached to the ceiling as well, at least a 5" crown should be. 

Before setting the beam, cut the studs level, and if possible, preload the beam/header by shimming the cripple studs, to insure all are snug/tight to the header.