Personally for me it would be Crowder and Thomas, but I suspect it will be Bradley and everyone else stays put creating a log jam that won't get sorted out until the trade deadline.
And just so I'm clear, I'd trade Thomas because I think Bradley will be the better long term back court mate for Fultz and Bradley will be cheaper to sign long term which I think is important for flexibility going forward. So even without Hayward I might look to move Thomas this year (I wouldn't just give him away but if the right trade came along, I would move him).
As for Crowder, I don't think he will deal very well with being benched, which would happen by bringing in Hayward and even if Boston doesn't I think Brown will overtake him at some point this year, which will be even harder for Crowder to accept (look at how upset Ray Allen got for being benched for Bradley and at that time Allen was past his prime and had already made his money). So even without Hayward, I might look to move Crowder before his value tanked by being benched.