+1,

Add rear QR to the list of things to check early on.

As I tried to make clear in my earlier post, there are almost countless possibilities, and it's often a matter of working though the list.

There are two intelligent approaches.

You could do it analytically, focusing on the most likely possibilities first.

OR, You can assume that the list is too long, and there's little basis for ranking by odds so far, so instead do the simplest, easiest and cheapest things first, ie. pedals, rear QR, torque cassette lockring, seat post/saddle clamp, cleats and latches, and similar possibilities.

Odds are about 50/50 that you'll find the problem before having to get in to anything more complex or subtle. If not, having eliminated the easy stuff, you can out o your thinking cap and start taking the bike apart.

Here's another trick I use that might help. I make up a small batch of "diagnostic oil" consisting of less than 10% of a heavy oil dissolved in a volatile solvent like naphtha. I apply to places of interest, one at a time and see if I find one where it makes a difference. The thin oil wicks in quickly and deeply and may cure the clicking for a short while. However you'll know where to put your efforts.

The key is to only tread on area at a time, and ride in between. If you treat too many places and the click goes away, you still won't know where it was.