I don't think Thomas would come off the bench if we got Teague. If we traded for Teague, he would be the back up point guard and occasionally play with Thomas, pretty much the Evan Turner role.
As to what they would want, I'm not sure. Value wise I think the deal you mentioned is in the ballpark though
I think there's a strong possibility he would. We kind of have a 'ceiling' with IT taking up so much usage. He's a defensive liability with high usage- perfect for the bench.
Yes he's an All Star, but that's because we've given him unlimited usage and free reign, and with some real stars here one day, that usage will drop significantly.
There's a good discussion about this on RealGM.
Slartibast had a good point about it...
His D-RPM is consistently and severely negative. And a metric that rates him as our 2nd best defender (behind ET!) flunks the eye test in historic fashion.
He's not the worst defender in the league but he's definitely in the bottom third.
He's a defensive liability who needs near superstar usage to maximize his offensive strengths and be a big net positive.
If you surround him with 3+ defensive roleplayers (AB/Crowder/Amir + Smart as 6th man) and let him be the offense, he looks great and the team functions at a decent level, but you've got a pretty firm cap on the potential. Bringing in more offensive star power in the starting line-up will reduce IT's usage and decrease his net benefit.
The best place for a very high-usage go-to scorer who is a defensive liability is as a 6th man.