Learn to love the IDW comics. Cyclonus, Scourge and the Sweeps (and Galvatron) weren't anybody.
Or watch TFTM again: Shrapnel and Thundercracker (and I'm not sure of the others) appear after Unicron creates Scourge and Cyclonus and the Sweeps.
Or remember that Cyclonus and Scourge travelled back in time in the UK comics and could have met those characters then.
There was some discussion of Sweep numbers here that might enlighten/confuse.