I think that when all ships of a legion have docked at the base, then they unite all of their abilities(att/def/scan/cloak) with the bases ability. When it comes to scanning, the base can have its own planet database. Legion members can use this database only when docked at the base. When players share a planet, it becomes permanent in the legion base, unless a flux is used.

An addition, the planets scanned for at the base only remain at the base, players can not take the info with them.