Freddie's lead-vocals are in the middle. They got some reverb (in stereo).
From 1:11 on there's a second track for harmonies, doubling and additional parts.
At 4:03 there's an additional track on the right side for another harmony.
This track does also the extremely high-pitched vocal extravaganza at 5:08, which imitates the guitar-solo (right channel). This is also done by Freddie and sounds great. The ''Ahh-ahh'' backing vocals in the chorus are two two-part harmonies, consisting of two voices by Freddie on the left side and two voices by Roger on the right side.
Info provided by Philipp