is there a way to apply ease in - out and be able to see the animation at the same time?
The only way would be possible is opening Bezier Editor directly from Layer Properties of peg or drawing and edit the value while looping. This however will be little bit difficult if you are using Separate instead of 3D path due to sync x, y and z to sync.
In that sense, using ‘Set easy for multiple Parameter’ tool menu would be easier although you will not have an option to see the change in real time.
Hmm, 3D path and bezier editor is the best solution so far, thank you.