Tip: Make a party with two of the required characters + a fast group damage dealer like Faris/Agrias/Squall/etc and you can clear those missions while you are farming the required monsters.
Another Tip: The next Event/Story/Lost Chapter will probably have lots of these monsters too, so if you are not in a hurry you can get a head start by completing it before tackling these missions.
_________________________________
Machinery x40
Balthier’s Lost Chapter: Thieves of the sky Pt. 10 (Normal difficulty) has 4 Machinery types in 5 waves. You can complete the mission in 10 fights.
Behemoth x10
Squall’s Lost Chapter: A Lion’s Heart Pt. 10 (Normal difficulty) has 2 Behemoths in 5 waves. You can complete the mission in 5 fights.
Cerberus x10
Story Act 2 Chapter 4: 4-44 Unending Thirst for Dominion has 2 Behemoths in 5 waves. You can complete the mission in 5 fights. Sadly, the best way to farm them (the raid co-op) is already gone. The only other alternative right now is in act 2 chapter 7, City of Dark Night part 2.
Thanks
To the DFFOO “Monster Hunter Guide“, an initiative to list all monster locations in the game (source).
To @xcaliblur, @mzpro2 and @infinitus who also contributed tips for these stages in our public DFFOO Telegram group, which can be found here: