Hi,
1.8 doesn't have cache component optimization, it's the new Unity 5 that changes the underlying system which nows becomes more optimized for component access.
else, can you reference the thread you read about this 1.8 optimization?
event/get/set variables also require somewhere to cache the PlayMaker Fsm Component, so yes any optimization would be improving this.
as for get/set property, I am not sure.
Bye,
Jean