Compared to the front, the rear is a trivial project.

Traditional shocks in the rear, not struts, and the shocks are mounted external to the springs.

No need for an alignment.

Replace the upper shock mounts while you are doing this.

The only difficult part of this will be removing two bolts holding each of the shock mounts. For some reason, Volvo used excessively long bolts with the exposed threads protruding below the car. The exposed threads tend to rot and when you remove the bolts from above, there is a danger of seizing or breaking the bolts. I'd spend a lot of time working the bolts back and forth with lots of penetrating oil.

Good luck.