First a couple of general assumptions.
Flo is almost assuredly going to want a veteran in the QB room. It would also make sense from the standpoint that should Tua go down, even for just a few games, we would want someone who could come in and "hold the fort" so to speak.
I'm going to go ahead, and rule out drafting a rd1 QB. Not that I would have an issue with doing so, I just don't believe there is much chance of it happening.
Here is a list of FA QBs, and ot ain't pretty.
Tracking the status and signings of all NFL free agents.
www.spotrac.com
It has always made sense, to me at least, that you want your back up to have a similar skill set, so the offense doesn't have to make wholesale changes, philosophically.
McCoy? Dalton? Barcley?
The FA list is ..........underwhelming
Trubisky might be an interesting choice.