I don't know if most of those dudes are clear upgrades, a few are just over the hill at this point and some could be an upgrade. I love Fitz for his attitude and the beard, willingness to air it out, and the fact he won't cost much but you will get a ton of INT's or Nagy will neuter him. Check that, I think he's still under contract? I also like Allen and Taylor but I don't think the Bears should trade for any of them. Try to sign one that a team releases and draft a QB. I thought Brissett was going to be decent but Indy benched him for an aging Rivers and then traded for Wentz, that tells you something. Who is likely to be a FA from that list, I would start there.
Without Robinson most of these QB's will be challenged in Chicago.