Too many young players and too many moving parts coming up to really think about a window, IMO. The "window" could close after this season if Lynch isn't replaced, Wilson doesn't develop and they don't shore up the O-Line and TE spot, or it could stay open for a very long time if all those things do happen.
If anything the Hawks are sending the message that they're planning to try to keep on winning how they have been winning; with great defense. I think it's the right strategy, but the length of the window is more dependent on what they have yet to do than what they've already done (e.g. with these two re-signings about 75% of the roster is still scheduled for FA in the next 18 months). Save for Tate they've done a good job re-signing their important pieces so far IMO (Bennett, Chancellor, Thomas, and Sherman), although TBF, as far as re-signings go, I do admittedly question how important of a piece Wright is (in particular) and Avril too. I think Avril is definitely worth his new contract to somebody (and maybe even Wright too), but if they're worth those contracts to the Hawks is a bit more of a question for me.