I can't find any reports linking the Celtics to Hayward before the Stevens hire. That said, here's the thing: that could very well be true. However, if Ainge were looking to trade for Hayward before he broke up the team, how do we know if he wasn't just looking for a complimentary piece to strengthen their chances as contenders? The Celtics consistently ranked in the lower half of the league on offense, so it's not inconceivable that Ainge may have viewed someone like Hayward as offering a potential solution to that. That doesn't necessarily mean Ainge feels Hayward is a building block or an appropriate piece for the rebuild. It's extremely possible that his feelings may have changed on him now that the team is moving in a different direction. Hayward hasn't hit his ceiling yet, but who knows if Danny just doesn't think the guy is someone you shape your future around.
Just saying, whatever may have transpired in the past happened when the team was still looking to contend; none of that necessarily still holds true at this point. Look no further than the rumors surrounding guys like Bass and Lee, who'd probably be viewed as a lot more valuable if the team had a realistic chance of being competitive this season.