I've played Rengar jungle and a lot of him top, but I don't understand why he leveled the bola first. If you look at the tooltip it only increases the slow and damage on it, but if you think about the situations a Rengar ganks you always use a 5 ferocity bola to start and another after to slow, so you will already be on top of the target.

Personally I level the shout first for more survivibility, it also makes more sence since he will be jumping in first and with that build he didn't have much armor or magic resist.