Gokai Galleon was previously owned by AkaRed. Before the start of the series, Akared, together with a younger Captain Marvelous and Basco to Jolokia traveled through space to recollect the lost Super Sentai powers.
The Super Mega Skyship, along with the other four Zords, were created by Gosei, as he knew the previous Gosei Mechazords were too weak against the Armada. The Skyship was never used for extensive space travel.
Gokai Galleon is the base and even living space of the Gokaigers.
The Super Mega Skyship was only used during battles or as transportation through the air, but not as a base or residence for the Mega Rangers
Power Ups and finishers were all given by previous Sentai members, when they trusted the Gokaigers in using it. These power ups were known as Greater Powers.
Only some power ups were given by previous power rangers. Most of them were created by Gosei and given at the time the Rangers needed it. No special name was given to these powers.