ArmorMech does NOT use luxury fabrics as far as I can tell. It only uses underworld metals.
Artifice also provides an epic Relic in the endgame (in addition to the epic lightsabers).
At tier 6, treasure hunting may also provide orange crystals.
It is worth noting that Treasure Hunting lockboxes can provide prototype quality gear on a critical result (although a sum of cash a little less than that invested is more normal).
1. Thanks, I am surprised I did not notice this. I was certain cunning armor used fabrics, I'll edit this immediately.
2. I haven't really covered what professions have in the endgame. I'll edit this in at some point, probably when I have better information regarding all crew skills.
3. See above.
4. I'm didn't cover this directly but I was assuming this was a given. I'll edit this in at some point. All missions can crit, including lockboxes.