The world I’m building is approximately 1/3 of the size of earth and it has 3 moons orbiting it. The orbits are all different but occasionally they have either a full moon or a new moon on the same day. I have a couple of questions. First, if all these moons were small (totaling to about 1/3 the size of earth’s moon) and slightly different sizes with different orbits, would the planet still be able to support life? If the answer to the first question is yes, then what would happen to tides and earthquakes and volcanoes? Would it be possible for a three mooned planet to function pretty similarly to Earth?
It is highly unlikely that a world as small as a third the size of the Earth would be able to retain an atmosphere so life would be unlikely unless perhaps in some form of ocean under an ice crust.
The tides would be very small and the moons themselves would be in danger of destruction if they approached too close to Earth due to Earth's tidal forces.
Such small worlds orbiting each other might better be described as a binary / tertiary planet depending on exact sizes.