You need a thicker jacket for mid April, not winter yet, but weather can be wintery, especially during the evening, depending on which direction the wind is blowing from. Better be prepared for the worst rather than suffer the cold.
You are not allowed to shoot the penguin parade, but I think you were referring to shooting the 12 Apostles with 85? Coach stops are usually at the designated spots and from what we did the last time, it was the best vantage point too. I think your combination of lenses is fine, ranging from 17-85mm. Just hope for the best weather.