The temperature of the produce at the beginning does affect the safety of the end product, so please do thaw them completely before canning. It will also make a difference in how many tomatoes fit in a jar. But once thawed, I would think that cold pack would be OK assuming you process them with the directions for cold pack. I'm sure there will be a textural difference but I don't know how severe it will be. I've canned from frozen before but I used them in sauce. I would think it would be OK for use in soups/stews etc but I would hesitate before using them in a stir fry.

Thanks lily! Good thought on NOT starting with frozen tomatoes--makes perfect sense.

As far as the texture goes-I'm hoping they will be more like stewed tomatoes than crushed tomatoes. Most of our frozen tomatoes are San Marzano Plum tomatoes, they are much "meatier", so we will just give it a try and hope for the best.