After reading the Slim Jetpack readme I found this:
I smashed the bundle to remove the annoying parts and keep the awesomeness. Slim Jetpack will track the updates of Jetpack modules, but is definitely INCOMPATIBLE with its original version because a lot of API functions had been mocked or removed.
Jetpack Lite it’s only a trimmed down version of Jetpack. So if Slim Jetpack is incompatible with Jetpack, the same applies for Jetpack Lite.
In fact. Slim Jetpack is another Jetpack “flavour”. Trying to use Jetpack Lite and Slim Jetpack together is like trying to have two Jetpacks at the same time (and that’s the cause of the error you’re posting above).
Sorry.
