I was thinking of you just last week and wondering how your garden is coming along. I've moved this as a separate thread to the Tomato Gardening forum as you requested.
I don't know how to tell the difference other then to suggest you label your containers before you put the seeds in the soil. I think most of us have made that same mistake. Once the new ones have grown a couple of sets of leaves look to see which are similar to what you have that are not labeled. You may not be able to tell any differences until the plants get some size and show their growing habit.
When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant.