Freeman is a pretty legitimate real-life QB, but he's much better there than in fantasy.
They're all worth rostering, but you only need two. I would try to trade Newton or Freeman to someone in your league who is weak at QB. You said you can't trade Freeman; you can definitely trade Newton. Romo has a week 5 bye; Freeman has SF that week. I would trust him to do well enough for one week. Or you could roster 3 QB's until after week five, use Newton during the bye and then trade him.