Blending Ciders

I was given a gallon of good cider from a local farm, unfortunately it already Potassium Sorbate added before I got it. I had already a gallon of a very dry cider sitting oak chips that I wasn't entirely happy with, so I decided to blend the two together.

My wife really likes the Woodchuck Seasonal Fall Cider, Which is a sweet cider with cinnamon and nutmeg, aged on oak. So I took one gallon of the two and added a small amount of those spices. I hadn't checked on the carboys until a week after I blended the ciders not expecting any fermentation because of the preservative. I happened to glance at them while bottling some mead earlier and saw what looks fermentation, not alot but it definitely seems to be there. There seems to be more in the non-spiced carboy but that is probably just an effect of the spices. So I will these sit and see what happens, the question is if I would be able to bottle these carbonated instead of flat as I was previously planning. A test of some sort to see if the yeast are active will have to be done.