I'm sure Capt will be along momentarily to show me where I'm wrong but I believe the 2018 pick is top 10 protected regardless and if not conveyed that year becomes unprotected in 2019.
Essentially it shakes out like this:
If the Kings finish outside of the bottom ten either in 2016 or 2017 then the Bulls will get their pick. In the year that the Bulls get the pick the Sixers won't have the option to swap picks since it goes to Chicago. In the other year they will have the option to swap picks. Then in 2018 they get the Kings pick unless they are in the bottom 10 again.
If somehow the Kings finished in the bottom 10 both of the next two years then the Bulls would NOT get a pick from Sacramento and the Sixers would have the option to swap picks both years. Then in 2018 the Sixers would get the Kings first rounder (top 10 protected) and the Bulls would get their 2nd rounder.
Darn it. I wanted to do something clever where I said that everything that was wrong was in boldface above and then there was nothing in boldface...but...
OK, there are actually two clarifications here.
First (and easiest), the Bulls will get our 2017 second rounder (56-60 protected, as we've already promised that portion to CLE via BOS) if we do not end up giving them a first rounder in either 2016 or 2017, not our 2018 second rounder.
Second, the 2018 pick IS top-10 protected, but it is only in play if we end up sending the 2016 first rounder to Chicago. Otherwise, we could potentially send both our 2017 (to CHI) and 2018 (to PHI) picks, and that would violate the Stepien Rule. If we do not send the 2016 pick to Chicago, the 2018 pick remains ours. Technically, we could probably have even further qualified the 2018 pick by saying that if we did not convey a first rounder to the Bulls in either 2016 or 2017, then the 2018 pick would return to being in play (that would not violate the Stepien Rule), but it does not appear from reports that we did so.