MYSTERY ISSUE. Doing my head in. Please Help!

[Evo]

Yes.

I have tried to suggest this earlier but you didn't seem to acknowledge it. Remove the rear shaft and take it for a drive as this will eliminate nearly half the vehicle. Are you 100% sure your tail shaft isn't touching when driving? Get a paint pen or some spray paint and paint the earlier mark and go for a drive if no marks in paint when you get back the that's 100% ruled out.

I did acknowledge and reply when you suggested to remove the shaft.
The unis, slip joint and balance was checked when it was taken out.
I haven't had the patience to check the shaft again, see what happens tomorrow.
Don't have any spray paint, or paint pens, was thinking of using some packing tape and wrap the section of shaft right over the crossmember.

There are also some seals on the inner side of your front wheel this area could be dry or full of crud and possibly causing an issue. Wouldn't hurt to remove and inspect at least.

I had a look as best I could when I did the hub conversion. Looks fine to me (not that I'm an expert), but I had hardly driven it before the problem started, so definitely no crud, and they don't appear dry.
Car was up on a hoist and noise is still present in 2H, so to me this would eliminate the front end drive line anyway.

Missed out on the diff too. Thought about it for too long...

Am thinking of investing the $350 I was going to spend on a used diff to have the diff stripped and inspected. If there is no issue, this price includes reassembly.
Sound like a reasonable price?

Have already spent about $650 to date on this issue...

Cheers

Evo