Trading for Hendo (and Harden) at the beginning of the season is a safer trade since you can go ahead and lock them up to an extension, but now you run the risk of him being unhappy and not signing a QO... which means Hendo's value is lower now than it would've been.
We can S&T him after the season when he becomes a RFA but not before. The rules changed for the receiving team in regards to their cap position but they are still allowed.
What Swedd said is how I interpret the situation too.
Hope Resurrected: "I think I can bring an attitude to a team as far as, ‘All right, no matter what, we are not losing this game'." - Kemba Walker
"Its okay to be bad; just so long as you're bad ass." - Keetch