So yea - completed it myself, mostly. Didn't get No Magic requirement (still can't figure out why). But it took me about 45 minutes (and 6 attempts I'd say) until I found the right team and got in a groove.
WOL, Rikku, Tilith, 2 Fryevia (1 a companion) and...King!
I started with Maxwell for her reraise; after dying a few times I decided to try Zarg and see if his buffs would help me out, but it wasn't sustainable.
Finally I decided to try King - his reraise ability is 18 MP compared to Maxwell's 45 for Sacred Song. With pistols/innate DW I was able to ensure he was the highest ATK unit and he even countered some dmg on the body for LB crystals, which helped in a pinch a time or two. In the end, I got the body and right arm down to slivers but actually killed the body first. Right arm came next after a few turns (it healed a bit, I guess?).
Once you get those 2 down, which is a FEAT, it was just cake. Raising King to make sure he ate the wipe, and chaining Fryevia's etc did the left arm in in about 4 turns.
Also, might I suggest bringing some of the new potion items from expeditions? They helped me big a few times where I needed to heal MP (other than Tilith, who had total refresh going on) to the entire party.
Probably won't try for no magic any time soon. I really just wanted to get the mastery and the fist so I can take it for a spin on O-man. May be able to break 1000 ATK!