I think that it will be fine, it's just too dry for your taste. Dry cider does taste sour-ish. If you check the sg again, it might be as low as .990 or so.
You can sweeten it without making it too sweet by using apple juice concentrate or sugar. The problem is that in order to sweeten it, you have to stabilize the cider first. That would cause the yeast to go dormant so it won't re-ferment. Then you wouldn't be able to bottle carbonate.
If you want to sweeten slightly and still bottle carbonate, you can use splenda which will not ferment. I'd try it- take an sg sample and then use that sample to see if a little splenda will make it less sour.
In my experience, campden does not kill wine yeast. I use it in all my wines and ciders. Sorbate is what is used to inhibit wine yeast by not allowing it to reproduce. So, I doubt that you "killed" your yeast when you added campden at 1.005. I added 5 campden tablets to my crabapple must (5 gallons) last evening, and I'm pitching the yeast today. Campden in around 50 ppm will protect wines and ciders by killing bacteria and wild yeasts, but not wine yeasts. As I said above, I think it kept fermenting and that's why it's so dry. If you check the sg, I bet it's down quite a bit. You shouldn't have to pitch fresh yeast, unless your sg really still is at 1.005 and it really did inhibit the wine.