I think this is definitely a situation where you look to trade. As much as this team needs a 3, Vesley/Lenoard will probably not be much better than Garcia, and probably be behind Greene/Casspi. A big is interesting, especially if Dally goes, but could you really survive a rookie/JT/Cuz rotation? Dally is more likely to be replaced by another vet.
And unless Knight falls, none of the guards will be any sort of upgrade, so a #7 pick will not help this team in the short term, and would only further muddle the longterm picture. The Kings are past the point of a barren team stockpiling talent, and should look for a trade partner who is.