Thanks all, didn't really think about working from my back, since I'm only "concerned" with #2 this approach does make sense.
As for the "metal", I've torn the head down as far as needed and nothing is missing, there is a bent rod on the #2 intake, so it is confirmed (at least by me) that the metal came into the intake but still don't know from where as everything is accounted for. I did run it back through the intake and up to the air filter, and nothing looks damaged, inside of intake looks "perfect". I did examine #2 glow plug and injector (as well as 1 and 3) and again they all look identical so I'm still stumped.
I am leery to replace and put back together until I at least have an idea of what caused the damage, but I'm just not sure where to go next...other than the oil pan so that will be next step (much better than separating tractor).
Also, going to bring the head to a machine shop and see if they can deck it, but some of the pitting looks pretty deep (relatively speaking) so not sure they could take off enough to make a difference.
New head is 2K, although on Ebay they have Chinese heads for $750...but are they crap or is it the same folks making the Bobcat/Kioti head anyhow.
Time will tell