I recently ran into a particularly pesky problem in which a Slick Slider refused to initlize properly with Instafeed. It was driving me up the wall, but the solution was one of oversight. I suppose you could argue that this is always the solution to programming problems?
Credit goes to Adam at The Northern Foundry and has to do with timing. That's to say, the Slick Slider was initializing prior to the Instafeed being populated. In hindsight, I should've known better, but this one went right over my head.
The solution is incredibly convenient on account of Instafeed's 'after' method, allowing you to initialize Slick once Instafeed's content was populated.