Do not attempt to weld. It will cook the bonding epoxy right away. I have done my share of welding over the last 35 years so i have a feel for this kind of thing.

Polishing the lugs with a buffing wheel will be enough to expand them and ruin the bond. My neighbor buffed his and his lugs disbonded and rattled around. Striking an arc would be instant death as the aluminum conducts heat super well.

I would remove both ears and machine a custom clamp. But i also have machine tools that allow me to do so. Maybe you have a machinist friend that could help you?