If the transaxle is quiet, then you can can the seals in situ if you're careful. Lots and lots of people futz this job up. So BE CAREFUL. The seal nuts also locate the diff carrier and tension its bearings. There is NO margin for error. Close is not good enough.
DO ONE AT A TIME!
MARK THE SEAL NUT'S POSITION, count turns (whole and part), carefully note and mark where it becomes free so you start it in the same place, and can return the nut to EXACTLY the same place.
The seal goes in from the inside of the nut. Light, non-setting, sealer around the outside of the seal and on the seal nut threads. Light grease on the seal lip. Replace the inner o-ring as well. Light grease on the o-ring. After the seal nut is back in place, make sure the splined, inner seal land pops in place over the o-ring -- not an easy task so make sure it does. Some people use the half shaft and the weight of the car to do the job.
When you're done carefully shim the driveshaft yokes as well.