
Tip: Make a party with two of the required summon/characters + a fast group damage dealer and you can clear the character usage missions while also farming the required monsters.
Microchu x30

Selphie’s Lost Chapter: With Trabia in Mind Pt. 13 (Normal difficulty) has 5 Microchus in 3 waves, completing the mission in 6 fights.
Kraken x20

The current Heretic event (The Veiled Magician) has 2 Kraken enemies in 3 waves, completing the mission in 10 runs of the co-op stage (which you are probably already farming).
Alternative:

Deuce’s Lost Chapter: The Power of Kindness Pt. 14 (Normal difficulty) has 3 Kraken enemies in 5 waves, completing the mission in 7 fights.

Thanks
To the DFFOO “Monster Hunter Guide“, an initiative to list all monster locations in the game (maintained by Marvan09).
To @xcaliblur, @mzpro2 and @infinitus who also contributed tips for these stages in our public DFFOO Telegram group, which can be found here: