I just see HC jobs open every year. Lots come from places that are unexpected.
As for Pittsburgh. That IMO is a long term turn around. The best they can do is go with another retread QB if they want to win.
It needs to get blown up. IF Rooney want to do that and like you said willing to give Sean all that time. Then yes.
Otherwise, I wouldn't touch that job with a ten-foot pole.
Baltimore is a weird situation. Sean is very strict with his style. I don't see him fitting in with Lamar. That's just me.