I wonder if all the other Gorosei are named after planets. Uranus, Neptune, and Pluto are already taken, so that just leaves Mercury, Venus, Terra, Mars, and Jupiter. The other 4 Gorosei can be Mercury, Venus, Mars, and Jupiter. Imu will be Terra
So we are basically having a whole Solar system at this point.
Sun - Luffy (Devil fruit)
Neptune - Shirahoshi (Poseidon) (hax ability)
Uranus - Another ancient Weapon (Weapon)
Pluton - Ancient weapon in Wano (Weapon)
Saturn - 1st Gorosei
Mars - 2nd gorosei
Mercury - 3rd Gorosei
Jupiter - 4th Gorosei
Venus - 5th Gorosei
I have no clue regarding Gorosei whether they are Devil fruit holders or Hax users like shirahoshi.
Earth - Imu. (Probably the earth god fruit user creating the redline)
Also the earth moons in one piece universe are 6.
Those 6 moons could represent the top tiers or other two god Fruits in the verse. Forest and rain.
6 moons can Roger/Xebec/Whitebeard/Garp/Sengoku/Kong(not sure)