teams for mihawk

For the 30 I'm going with lion zoro and vivi I wondered what other characters in should use?

For the 40 I'm going to go laboon and vivi. Should I level up laboon? And what other characters should I use?

And should I evolve laboon?

The rule for laboon + vivi is that vivi must be able to heal 50%+ each turn. With Princess Vivi around level 73~ (heals 2k+), your team shouldn't pass 4k health.

A good team for this is as follows:
Princess Vivi (73+, so 2k+ heal)
Laboon (as low level as possible)
Red Crab
Blue/Purple/Yellow Crab
Nuke (anything red with 1k+ attack)
Nuke (anything red with 1k+ attack)

The key is to make sure your heal is always more than 50% your max health, so Laboon's effect always kicks in.

Since your health is low, and damage not that high, the mobs before Mihawk can be hard, but are beatable with the team above.