Wow, Allison, maybe I missed it, but I've never seen sugar in light sour cream.
Here's a link to Daisy's light sour cream ingredients. No sugar.
Here's a link to another page that lists a ton of light or red. fat sour creams. None have added sugar, but a few do have strange things like tapioca starch (not good) and gelatin.
Was sugar in the ingredient list or are you talking about grams of sugar on the label?
All milk products will have grams of sugar because milk naturally contains lactose, so what you want to do with them (and with all things, actually) is look at the ingredient list for any added sugars.
Ruth's right--it's very hard to find taco seasoning that's okay for Phase 1, and technically safe for any other phase. I did find one once that was just spices, but I'm forgetting what the name of it was. Read the labels carefully. One easy way is to go to a local spice store and see what's in their mix. They often have taco seasoning mix that's just spices and nothing else.

If you're intersted in making your own, check out the links for
Taco Seasoning Recipes in the Recipe Forum.