What I'd try to do:
Trade 4 picks, Harkless, Ezeli, and any filler it takes for George or Butler.
Those picks would be our 3 this year (with ours being lottery protected, with next years being top 10 protected). This means we'd probably still keep our pick, and trade a pick next year around 20.
The other being our 2019 pick, top 10 protected.
If something goes wrong (such as PG not resigning with us after next year), then we trade one of Dame/CJ for a high 2019 pick, and tank so we keep our 2019 1st.
We'd still have our top 10 2019 first, have another extremely high pick for the Lillard or McCollum trade.
We also be more likely able to trade Crabbe and Turner.
So we'd reset with 3 picks, and have some cap space to try to do some things or take salary for extra picks, etc. We'd still have whatever became of Nurkic, Vonleh, and Layman.
Basically, it's a risky move, but minimizing the risk as much as possible to be able to trade 4 draft picks while still not mortgaging away the future should things go wrong.