I'm doing the The Hope You Cannot Let Go instance now, thanks.
Do you guys know how to defeat Coelacanth on Malangdo Culvert? Using water armor gets me killed by LoV, not using it gets me killed by water ball.
Lure the Coelacanth (red dot) to the south of the wall marked in blue, stand on the opposite side (green dot) and throw bombs. If it starts moving towards you, just run for it and lure it there again. Use your Homunculus to lure so you don't get JTed to the afterlife.
I know this works because I used to do it long ago with really bad gear.