I keep reading about assumptions that the #3 pick is intended to be used in a trade. Hearing that the Celtics turned down the #3 for Jimmy Butler makes me think they really want a guy in this draft.
However, they'd still love to have to have an additional trade asset besides the 2018 Brooklyn pick (which they also intend to use on a guy they really like, assuming he's available at that slot).
So they trade their best asset at #1 down to #3 where they think they can still get their guy. Hold on to the 2018 Brooklyn pick to hopefully do the same thing.
The pick from PHI (2018 LAL/2019 SAC or PHI) is the pick they intend to use as a trade asset along with other future picks (Boston 2018, Memphis, LAC etc). Not trading the #3 this year (unless a super deal came up).
I'm starting to think the guy they want is Isaac, viewing him as a young KG type (who was picked 5th in his draft).
This allows them the option of cashing in draft picks (George, Butler), signing free agents (Hayward, Griffin) but also building a young core of high lottery picks with all of the Brooklyn picks (Brown, Isaac, Doncic). If it works out, it's brilliant.
Anyway, just an idea that this is what they are thinking.