Don't think you can justify trading all three (plus more salary and picks) for Davis at the moment. That'd absolutely kill our depth and make us so top heavy that our bench and young talent would be depleted. That'd be putting a TON of eggs into one basket, which I'm not sure is smart.
However, this summer I'd probably do something like a Smart S&T, Tatum, and the LA pick and Memphis pick for Davis, which would leave us Brown and Rozier. A Kyrie, Brown, Hayward, Davis, and Horford starting five is insane, and we'd have a solid bench with Rozier, Morris, Theis, Baynes, and whatever ring-chasing vets we could get.