solder/join single copper filament to contacts (speaker tweeter)
Other: Rebuild the broken terminal piece, but place it closer to the existing wire ends. I guess you can fasten it well with epoxy. Solder the existing wire ends. Insert a couple of drops of some acid free permanently soft silicone material which dampen vibrations so that your new soldering joints do not enjoy any bending which could come along the wires.
The thickness of the dampening material around the filaments should grow slowly and gradually towards the soldered area to be effective.