You should read Climbing Anchors by Luebben. It goes over sport and TR anchors very well.
As far as a PAS goes, sure you can use 2 PAS's but I will tell you that the PAS isn't what you need to be worried about when it comes to redundancy, it's the anchor. As long as you're not using your PAS beyond it being a rap tether and are continuing to monitor its wear, just as you would with a harness it has the exact same strength rating as your belay loop which you trust without backup when you rappel.
I'm still a little concerned about your rope as it looks short for most crags.
Lastly I'm not sure where you'll be climbing but if you're going to be setup TRs on bolted routes just make sure you have a safe way of accessing the anchors from above. A lot of times the bolts are over the edge of a route and the last thing you want to do is factor-two on your PAS.
Don't do it by yourself the first few times. While anchor building isn't rocket science, if your anchor fails while TRing, your climber will deck and will get hurt or possibly die. So... Read some books (Luebben's Climbing Anchors is a good start) but have an experienced mentor come and check your knowledge and setup.
Climbing anchors can be somewhat situational, depending on the crag, but usually if there's two bolts up top or chains you can use a pretty simple setup that isn't too complicated and can be learned pretty easy. But please have someone check your setup.