You should be able to make the scripting work in the montage with the resizeClip function. With that you should be able to make all the clips as large as they can be, but the clips will be consrained by Wavelab by their file size. The markers should move with the clip size, since they were originally attached to the ends of the clips. The following clips and markers should move if the montage is left with Track Ripple on.
I haven’t been able to get it to work yet, but it’s only because I’ve never tried scripting before and I can’t get the syntax to work. But it should work I think.