Stockpile Spent!
So my plan was to pop up to 3 chests. If I saw the "Belligerent Bang" message I kept going, if not I opened the Terminal Coffer.
Mars (40)
14 Mimics
3 Loud Thuds
2 loaded rainbow chests on Enter (Loud Thud)
21 orbs didn't give the "Belligerent Bang" message
Loud Thud drops were: Voidhand: DRK, Voidfoot: SAM, Footshard:DNC, Cypress Log, and a Tenkomaru (Pulse)
Venus (16)
4 Mimics
4 Loud Thuds
0 loaded rainbow chests on Enter (Loud Thud)
8 orbs didn't give the "Belligerent Bang" message
Loud Thud drops were: Cypress Log, Bewitched Pumps, Vexed Gages, and a Volte Cap
Other observations were that the "Thud" drops seem to be better overall then they used to be. It was a bonus to get one of those more expensive Dynamis shards. For Mars Orbs the Terminal Coffer was almost always just a "Noise" for me when I opened it. Once it was a "Thud", so based on the small sample I did here I would say on a Mars Orb it would be a pretty low chance for the Terminal Coffer to be a "Loud Thud". For Venus Orbs the Terminal Coffer was always a "Thud" when I opened it.
I did get the 5M gil once, it was from a Mars Orb and that character was in a party and was the only character that entered the BCNM. Also on that run I received zero "Thuds" when opening chests.
Out of the 56 used orbs traded to Greyson I never got a new orb returned to me. Orange/Apple juice was the most common item returned followed by SP Keys, and Copper Vouchers.