How might I progressively alter objects in an array?

Question

I have an array of objects on a path and would like to progressively alter them. For example, I'd like the objects to blur and lose opacity as they get further down the path.

A solution I tried for opacity was to use a color ramp with camera data which effectively faded out the objects as it got further away but this was limited because: a) distance was not always equal to progress on the path if it curved b) the opacity was a gradient across the objects when instead I'd like each object to get entirely less opaque (e.g. object 1;100%, 2;80%, 3;60%, etc. etc.)

Any help on what approaches may put me on the path to achieving this would be very helpful!

Note: I tried to post an image of my progress so far but it said I needed more reputation points : (