You don't "need" Epic Omelette, esp for a warrior. But I might take one or two. Keep in mind that Omelettes don't stack so they can crowd your inventory.
Medipack and Elixirs of Galade are very strong potions so a large stack of those might be sufficient .
The challenge with the Sewers is that once you're in, there's no escape so if you're under prepared, you're rather stuck.