It seems that the rear main seal would require that the engine and transmission be separated, and probably the clutch, as well.
The oil pan, valve covers, CV shafts, inner seals, and hubs can be done without pulling the cradle, even.
The transmission/motor mounts can be replaced fairly easily. Be sure to support the engine and transmission while replacing the front and lower mounts.
For the CV shafts and hubs, be sure to replace the axle nuts. If the "hubs" are the rear wheel bearings, the hubs should come with the wheel bearings and axle nuts.