Can't get my Lerp to work smoothly with Lerp or iTween

Hi, I got a main character gameobject on a path using iTween and I got "zombie" characters behind the character as a child of the main. All I want to do is smoothly move the zombies up from their position behind the player and move forward when something happens.

I have used iTweens MoveUpdate for this before in the update function and it worked as expected a few months ago but now it won't on this new project. They don't move in a straight line and their positions are all over the place. I used to just do this,

 iTween.MoveUpdate(Horde.gameObject, iTween.Hash("z", 1, "easetype", "linear","islocal",true));

but now it doesnt seem to work. Local space is ignored I guess and theyre all over the place.

I have tried Vector3.Lerp as well, but they just JUMP from point A to point B, no smooth movement. I have code for that as well if need to be shown