Would cable or bad connection cause the drive to make this strange sound, or is this looking like a bad drive at this point?

I've heard of simple cabling issues causing the clicking, yes. It also can mean a bad drive, too.

Don't be afraid to take the cables off and squeeze them as described in the FAQ. Make sure to read through the drive upgrade guide before doing so, so that you know how to remove the glue without damaging the cables.

And if you don't have standoff washers yet, add them.

See if any of that fixes it first.