Unless the Killer Bow's insta death procs, no she can't. My Lenna is lvl 27 with a 15/15 Killer Bow and the only enemies she can OHKO are the Goblins. Though I haven't equipped her with a Hyper Wrist, I can try that I guess.
I actually have a Killer Bow horror story.
1) Retaliate meta with Cloud
2) Wakka is one of my back row double cut bots
3) On Round 3/3 trash, Wakka targets Cloud, normal attack
4) Cloud's Retaliate pose wears out right before Wakka attacks
5) Wakka hits Cloud for 100, Cloud keels over
Oh, Killer Bow.
Is now a good time to pop my 50 mythril? What's the consensus on the current higher-odds gear?
The very pragmatic min-max for the next month is to wait for Vanille event (presumably in a few days) and blow it on the XIII banner. Not only is the Vanille event tricky without XIII RS gear, the next set of paintings also end with XIII elites.
But those books give great soul breaks to Tyro.
Heailng Grimoire seems like hot garbage to me - two bars for an AOE heal. Yeh, AOE heal is good, but it feels like you'd need a shit ton of set-up (meaning you need to use Tyro's turns during trash), and Tyro is pretty lackluster at dealing damage to begin with. Compared to 60% damage mitigation which is absolute everyone-is-your-new-best-friend Jesus-tier, it's like it drew the short end of the ugly stick.