Four options for different scenarios:
1) Duplicate the layer, then replace its source. Select the layer which you wish to replace in the timeline, then hold down Alt while dragging an item from the project panel onto the the layer(s) in the timeline.
2) Parent a new layer to the old one. Hold Shift while dragging the layer’s pickwhip from the new layer (the child) to the old layer (the parent). The child layer will move to the position of the parent (because of the shift key) and will follow along with all transforms (because of parenting).
3) Link the properties you wish to mimic from one layer to another. Select the master properties and choose Edit > Copy with Property Links. Select the follower layer and paste.
4) Save your modified/animated properties with an animation preset. Select these properties from your main layer, then choose Animation > Save Animation Preset… which will allow you to store these a portable FFX file. Select the follower layer, then Animation > Apply Animation Preset… and choose the FFX file you just saved.
Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive | RenderBreak [blog] | Profile [LinkedIn]