Zodiark would be difficult to solo tank, the 30 sec dmg debuff can early one shot you unmitigated, and you prolly would still get 2 shot if you do mitigate his attacks, and u will need very good healers to keep you on top of things. Solo healer on the other hand is very possible.

However light mommy on the other hand.....solo tanking is actually feasible if you use ur cooldowns appropriately.