The 'Human-like alien Federation' is an empire.
History 2003 series
Not much is known about the Federation, other than they've forced more than 150 planets under their rule in the past decade before the turtles arived and have been the mortal enemies of the Triceraton Republic
One of their greatest scientific minds, Professor Honeycutt, had plans for a teleportal, a device that can transport people without need for ships. But General Blanque, head of the military, planned to use it for transporting bombs. But as he had no control over the Professor, Honeycutt refused. But during an electrical storm, Honeycutt went to help his robotic assistant Sal, who was tangled in wires, they got struck by lightning. Because Honeycutt was wearing a telekinetic device at the time, his body disintegrated while his mind was transferred into Sal. Blanque, who was monitoring everything, knew he could take the plans by force, as robots had no rights in the Federation. His troops chased Honeycutt, called the Fugitoid into the nearby city, where he was incidentally saved by the Turtles, who were brought to D'Hoonnib through accidental use of the transmat. But Honeycutt was captured by the Triceraton, who also heard of his teleportal through Blanque collaborative aide, Lonae.
Blanque lead a task force to retrieve the Fugitoid, arriving just as he and his Turtle companions had escaped the Triceratons. Immediately, a battle begun between the two sides until the Fugitoid escape due to the transmat.
The Federation followed the transmission to Earth, where they secretly met with the Earth Protection Force, promising protection as well as new technologies from other aliens in exchange for the Fugitoid, who had just returned to Earth from the Utrom homeworld after the Triceraton invasion. Once Honeycutt was captured, hidden Federation forces began to attack the Triceratons. But once they tore Honeycutt open and accessing his data files, Blanque discovered that he had deleted all plans on the teleportal and used the opportunity to download a virus into the Federation ships, causing them to crash into each other. Prime Leader Zanramon took the window of opportunity to attack the Federation at long range but Mozar refused and assisted Traximus in a coup d'état. The leaders of both sides were deposed, put in neighboring prison cells, where they began trying to pound the glass to get at each other. Traximus rescued the stranded Federation soldier and returned them home as a first gesture of peace.
Afterwords when blanque was In prison along tramcaraton prime leader turns out former general blanque high command unknowingly to him where a bunch of realest dreamers who dreamed of restoring the civilian government and make it a real democracy again where the federation military decided to turn in decided to turn in there power to the puppet civilian government making them the real government again have them write a new constitution with governmental power being on planets in frontier which security and that military had better track record on it the civilian ones which would be subject to civilian governmental every so often and aliens which was even to the federation human population had citizenship and full voting rights.