Right, I haven't tested for breakdowns as I was planning on having the day off from this thread
But I did a bit of armor decay data gathering which has illuminated an interesting wiki error.
First up, trying to get Impact and Cut, I went to see some Formicacidas. It turns out I wasn't getting enough decay for them to be impact/cut. I was getting 23 dmg decay in Zombie - the only sensible explanation of that was that they are doing Cut and Stab and something else that Zombie protects 1.0 against.
I went back with Goblin+6A. The 6A does not decay. The Goblin decays as a 9 dmg hit would. Thus, rather surprisingly:
Formicacida (Weak) does not do Impact and Cut: it does
Cut,
Stab and
Acid
[Deleted stuff about Molisk]