Here's my setup for Summer Melu. She uses 2 bond up CEs but if you could care less about bond, MLB BG clears her easily.
Hakunon is needed so Melu can get her Quick/Buster or Buster/Buster cards + stars. You've got 10 tries for the card shuffle and sometimes she drains 1 CS from me.
A Mighty Chain with NPQB may leave Grand Olga with like 50k hp left. NPBB chain is better.
Of course the Earth Olga is SKY attribute. Seriously, fuck them.