On the second ticket,

does it say 'failure to yield' or 'failure to stop'? Sounds like the former is the cause of the accident, not driving without a license. You may have stopped, but you failed to yield to oncoming traffic. If it is the former, there is nothing to argue; if latter, you can argue, but probably won't make a difference since there is no witness. As another friend pointed out, driving without a license is a much more serious offense than failure to yield (or stop) in terms of law (not in terms of actually damage in this case).