Learning to solo Last Stand can be a very exciting adrenaline rush experience at first. With the mad dashes to destroy and kill stuff at two locations simultaneously within a limited time to be prepared for the next timed events.
This is the only mission I take the Cannoneer to and he works great here with his very wide range and ability to hit over obstacles. Any main can solo this with a good Cannoneer and Hwarang.
This mission is time-based which forces you to spend at least 23 minutes on it, but 15 reward boxes in the end kinda makes up for it, specially if you can solo.
Spear Main + Sheriff + Hwarang.
Attila is probably the best merc to have for all Zulu TBSs, but my alt has none so I had to use my usual TBS mercs before Zulu was added, Hwarang and Sheriff. Their ranged attacks work well for clearing spider webs in this mission at least.
Spear Main + Hwarang + Champion.
This one is another simple mission, if you can manage to lure the boss away from mobs. The objective is to meet and greet a big mother snake boss after killing some of her children on the way, and torture her until she tells you to stop. Basically, it's a boss spiking mission.