4 level 1 players start in Limsa

[BRVV]

As premade group of 4 you are able to go together into the dungeon, even without a healer.
It might be a bit harder and takes longer but you still should be able to clear it with 1 tank 3 dps.

I want to add: Arcanist has a healing spell even as a dps. So you can go in with 3 dps and a tank and the arcanist could spam his healing spell. You can also all spend some gil on potions and give them to your tank.